This PDF file contains the front matter associated with SPIE Proceedings Volume 6984, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

The structure and static dielectric permittivity of BaRO₃(R=Ti, Zr) thin films as a function of epitaxial strain are determined by using first-principle density functional theory calculation based on pseudopotentials and a plane-wave basis. It is found that BaTiO₃ thin films under compressive misfit strain can be grown more easily than those under tensile misfit strain, while thin films of BaZrO₃ can be grown more easily under tensile strain. The static dielectric permittivity of BaTiO₃ thin films under different misfit strain is obtained by calculating optical phonon frequencies and Born effective charges using density functional perturbation theory. The zero-temperature dielectric permittivity of ε₃₃ increases to the maximal value under compressive misfit strain, while the ε_11/22 reaches to its maximal value under tensile misfit strain. For BaZrO₃ thin films, the dielectric permittivity ε_r changes little. However, ε_r exhibits non-linear characteristics under tensile strain, which reaches to the maximal value under misfit strain of ~1%. This unsymmetrical dielectric behavior caused by strain is attributed to soften phonons in BaTiO₃ or BaZrO₃ thin films.

A heterojunction of heavy phosphorus doped hydrogenated nanocrystalline Si (nc-Si:H) film with p⁺-type crystalline Si wafer was prepared and measured to investigate stress effect on electronic characteristics. According to electrical experiments, the yielded structure was demonstrated as a semiconductor backward diode. Energy band gap of nc-Si:H was inferred to equal that of amorphous Si:H because nanocrystals imbedded in amorphous Si:H matrices. Mechanical stress effect on electronic characteristics for the operated unit was interpreted by stress-induced defect states since a mass of defects distributed in inhomogenous material. Reverse current showing good linearly dependent on applied stress with a effectual method of conversing mechanical signal to electronic one before breakdown was indicated.

We investigated the electric field dependence of photoluminescence (PL) spectra in four kinds of GaAs/AlAs multi-quantum well (MQW) structures. Only one of them exhibited various PL spectra in spite of having a similar sample structure in the MQW. The PL spectra reveal several signals in the shorter wavelength region due to the combination effect of interface roughness and Γ-Χ scattering. We also estimated the carrier densities of excited states by observed PL intensities and calculation of overlap integrals of wavefunctions between electron and heavy hole states. The observation of PL signals from excited states in the MQW provides fruitful information on carrier densities and structural imperfection of MQWs.

Using Landau-Devonshire(LD)-type phenomenological model, we investigate the phase diagrams and in-plane anisotropic misfit strains of single-domain single-crystal (110) Ba_0.6Sr_0.4TiO₃ film epitaxially deposited on (001) NdGaO₃ substrate. Investigation indicates that film thickness plays a crucial role on formation of in-plane anisotropic misfit strains and stable phases. As is consistent with results of experiment that anisotropic strains have greatly changes with increase of film thickness. The anisotropic strains induce tetragonal phases which only contain in-plane spontaneous polarization component. These phases do not exist in BST films of the same composition under isotropic strains. Moreover, calculation manifests that anisotropic in-plane misfit strains are almost completely relaxed when film thickness is larger than 600nm, which has been reported in experiment.

First-principles calculations have been performed to study the adsorption of Aluminium(Al) on the Si(001)2×1 surface. The optimized geometries and electronic structures of the adsorption system were investigated. The adsorption energy at various adsorption coverages(Θ) from half a monolayer(ML) to one monolayer has been calculated. The most stable adsorption sites were consequently determined to be HH site and T3-T4 site, respectively. There is obvious evidence that the asymmetric aspect of the Si-Si dimer becomes the symmetric one which has been observed at the coverage of 0.5ML or 1ML. In addition, the bond length of Si-Si was found to be considerably elonged upon the Al adsorption. The work function calculations have shown that the aspect of work-function change for the Si(001) surface due to the adsorption of Al is different from that of the alkali metals adsorption reported in some previous works. The surface formation energy was also calculated. The absolute value of the surface formation energy was found to decrease with increasing coverage indicating that 1ML is not a saturation coverage. In order to shed light on the nature of the Al-Si bond and the character of silicon surface, the density of states and band structure of the system were calculated.

The initial stages of multilayer Fe thin film on Cu(100) surface prepared by pulsed-laser deposition(PLD) were simulated by means of kinetic Monte Carlo(kMC) method. We focus on examining the effect of high instantaneous deposition rate and energetic adatoms on nucleation and the surface roughness of Fe film on Cu(100) surface. The simulation results show that high instantaneous deposition rate alone is insufficient to explain the layer-by-layer growth in PLD, and it is the combination of the kinetic energy and high instantaneous deposition rate that leads to improved quality of the film surface.

In this paper, we report fabrication and evaluation of an organic light emitting diode (OLED) with organic multiple quantum wells (OMQWs). We fabricated the OMQWs using organic molecular beam deposition, consisting of TPD (N,N'-bis(3-methilphenyl)-N.N-diphenyl benzidine) and DCM (4-(Dicyanomethilane)-2-methil-6-(p-dimethilamino-styryl)- 4H-pyran). We measured photoluminescence (PL) and electroluminescence (EL) properties to characterize the OMQWs. In both measurements the peaking wavelengths clearly become shorter as the thickness of the QWs becomes narrower. This result obviously indicates that subband states are achieved in the quantum wells. In addition, we did numerical analysis to assign the effective mass of electrons in the OMQWs. Consequently, the effective mass of electrons can be estimated as 0.05 m₀.

ZnCdS/SiO₂ nanocrystals with core-shell structure were fabricated by Micro-emulsions method via the hydrolysis of tetraethyl orthosilicate (TEOS). Using XRD and TEM, the size of capped nanocrystals was around 22nm with the uncaped round 12nm. Emitting peaks in PL spectra of ZnCdS shifted from 390nm to 540nm by adjusting the proportion of Zn/Cd. The water solubility and optical property are both obviously enhanced after the capsulation of SiO₂.

Rhodamine B was embedded in a matrix of mesoporous silica films by the sol-gel method. A precursor sol containing tetraethoxysilane, ethanol, surfactant cetyltrimethylammonium bromide (CTAB), water, rhodamine B and acid catalyst was prepared by sol-gel. Depositing the precursor sol on a substrate wherein evaporation of solvent and water causes the formation of mesostructured films on the substrate surface by evaporation-induced self- assembly process. The nanocomposites films were obtained by embedded rhodamine B in the pores of mesoporous silica films. The mesoporous film was characterized by XRD and TEM, UV-VIS-NIR. The luminescence was measured and a red shift in the peak of the luminescence spectra compared with rhodamine B in the film and rhodamine B in water was observed, which may be interpreted as reflecting a decrease in the dipole moment of the exited molecule. The results show the luminescence action of rhodamine B in nanopores approach to single molecule's. This relates to the restriction of nanopores to organic molecules. The degree of aggregation decreases for the mesoporous silica films may be regarded as a hydroxylic, relatively polar environment, less polar than water although controversy still exists on the role of water in causing aggregation.

In this paper, we report the band offset and interface charge density properties of the nc-Si:H(n)/c-Si(p) heterojunction (HJ) diode by the capacitance-voltage (C-V) measurement and theoretical modeling. By employing the ideal anisotype HJ capacitance model and numerical C-V matching method, the band offset and heterostructure interface charge density of the nc-Si:H/c-Si HJ have been obtained and analyzed. An interface charge density on the order of 10¹¹ cm^-2 is estimated via the numerical C-V matching technique, and the low interface defect density has also been confirmed by the frequency insensitive C-f results.

X-ray absorption near-edge fine structure, optical transmission, and photoluminescence spectra have been measured on an Al_0.25In_0.75N thin film. With the aid of a novel procedure developed for analyzing the transmission spectra, together with a bandtail theory based on the calculation of density of occupied states and the carrier-phonon interaction, we have obtained the temperature-dependent optical properties of the thin film, such as band gap and Urbach bandtail parameter.

We have studied the weak localization (WL) effects in the electron accumulation layer on InN surface. Both the spin-orbit relaxation time τ_so and the electron-phonon scattering time τ_e-ph have been extracted from the WL analysis. We have observed that 1/τ_so increase with disorder and τ_e-ph exhibits a tendency to change gradually from the characteristic dependence 1/τ_e-ph ∝ T³ in the pure case to the form of T²l^-1 with increasing disorder.

We propose an approach to achieve single layer of Si nanodots arrays on insulating layer by using KrF pulsed excimer laser irradiation on ultra-thin hydrogenated amorphous silicon films followed by thermal annealing. Under the suitable fabrication conditions, the area density of formed Si nanostructures can be higher than 10¹¹cm^-2 as revealed by AFM images. The size of formed Si nanodots is 3-4 nm for sample with initial a-Si:H film thickness of 4 nm. Room temperature visible light emission can be observed from laser irradiated a-Si:H film after thermal annealing. The results on electron field emission properties were also presented in this paper.

Semiconducting high manganese silicides (HMS) have attracted great research interest in the past decades for potential applications as novel optoelectronic and photovoltaic devices integrated on Si chips. The fundamental electronic properties in HMS are still unclear, and the band-gap energy was reported to scatter from 0.42 eV to 0.98 eV in the past decades. In this work, single phase semiconducting Mn₄Si₇ precipitates and thin films have been synthesized by ion implantation. Optical absorption spectra obtained by transmission measurements demonstrated the existence of a direct band gap in all samples. The band gap values varied in the range of 0.77 eV to 0.93 eV, corresponding to varied strain states due to different microstructures. The electronic band structures of Mn₄Si₇ under different strain states have been theoretically investigated by means of a full-potential linear augmented plane wave method and compared with the experimental results. From ab initio calculations, the Mn₄Si₇ compound is found to be a pseudo-direct band-gap semiconductor with a fundamental gap increasing linearly with the compression along c- or a-axis. This trend is in good agreement with the experimental results.

Ion milling-formed n-on-p diodes of HgCdTe were studied by photoluminescence spectroscopy. A sequence of spectra measured across a square junction show that the luminescence peaks of the ion-eroded region shifted strongly to shorter wavelength than those defined by monolithic material. This shift may be well interpreted in terms of Burstein-Moss (BM) effect and is important to device fabrication.

A reel-to-reel system which allows simultaneous deposition of both sided long length epitaxial CeO₂ buffer layers on biaxially textured Ni-5at.%W tape with direct-current (d.c.) reactive magnetron sputtering method is described. Deposition is accomplished through two opposite holes in the cavity by inverted cylindrical magnetron (ICM) sputtering guns. The films were characterized by means of x-ray diffraction (XRD), and atomic force microscope (AFM). The samples exhibited good epitaixal growth with c-axis perpendicular to the substrate surface for both sides. FWHM values of out-of-plane and in-plane for both sides were 3.2° and 3.1°, 5.3° and 5.1°, respectively. AFM observations revealed a smooth, dense and crack-free surface morphology. Biaxially textured CeO₂ buffer layers up to 100-m length could be fabricated with production speed of about 1.2m/h. A 1-m CeO₂ film was obtained with uniform thickness of 50nm, and Δω of 3-3.5° and ΔΦ of 5-6°. Subsequently YSZ barrier and CeO₂ cap layers were deposited to complete the buffer layer structure via the same process. Epitaxial YBa₂Cu₃O_7-δ (YBCO) films grown by d.c. sputtering technique on the short prototype CeO₂/YSZ/CeO₂/NiW conductors yielded self-field critical current densities (Jc) as high as 1.3MA/cm² at 77K. An Ic values of 103A/cm² was obtained for double-sided YBCO coated conductors.

Epitaxial Ba_0.6Sr_0.4TiO₃ (BST) thin films were deposited on LaAlO₃ (LAO) substrates with the conductive metallic oxide La_0.5Sr_0.5CoO₃ (LSCO) film as a bottom electrode by pulsed laser deposition (PLD). X-ray diffraction θ~2θ and Φ scan showed that the epitaxial relationship of BST /LSCO /LAO was [001] BST//[001] LSCO//[001] LAO. The atomic force microscope (AFM) revealed a smooth and crack-free surface of BST films on LSCO-coated LAO substrate with the average grain size of 120 nm and the RMS of 1.564nm for BST films. Pt/BST/LSCO capacitor was fabricated to perform Capacitance-Voltage measurement indicating good insulating characteristics. For epitaxial BST film, the dielectric constant and dielectric loss were determined as 471 and 0.03, respectively. The tunabilty was 79.59% and the leakage current was 2.63×10^-7 A/cm² under an applied filed of 200 kV/cm.

The oxide ion conductor material, Cu doped Bi₄V₂O₁₁ (BICUVOX.10) powders were prepared by the combined EDTA (ethylene diamine tetra acetic acid)-citrate synthesis technology. The dried gel was annealed at various temperatures (400-600°C). Powders derived from dried precursor resulted in the mixed phases to BiVO₄ and high temperature γ-phase of Bi₄V₂O₁₁ by heat-treating below 400°C, and furthermore, yielded only pure γ-phase above 500°C. A simple surfactant-stabilized method was investigated for the preparation of well-dispersed nanoparticles. It was found that the deagglomeration treatment to the precursor by surfactant polyethylene glycol (PEG) 4000 was effective in improving the size distribution and annealing conditions of the BICUVOX.10 material.

In present study, the biaxially textured CeO₂ buffer layers on Ni-W substrates have been prepared by chemical solution deposition (CSD) with cerium acetate as the starting precursor, mixed with solvents of Propionic acid, Isopropanol and Acetylacetone. Typical XRD θ-2θ scans and the pole figure display well out-of-plane and in-plane textures of CeO₂ films. SEM and AFM results suggest that the buffer layer have uniform and smooth surface. Meanwhile, the effects of heating rate on CeO₂ formation starting from the precursor solution have been studied using differential thermal analysis (DTA). And the further analysis is given by XRD results for precursor xrogel at the corresponding temperature. Detailed high temperature optical microscope (HTOM) photographs investigate the surface characteristics evolved with temperature.

Development of new semiconductors with high mobility is strongly needed to realize future system-in-displays. To achieve this, we have been investigating electric field assisted metal-induced lateral crystallization (MILC) of a-Si_1-XGe_X (0<X<1) on insulating substrates. This realizes uniform crystal growth of SiGe with all Ge fractions. In addition, thin-film transistors (TFTs) with Schottky source and drain structures were fabricated, which showed good ambipolar operation characteristics. Present paper reviews such our recent progress of electric field assisted low temperature SiGe growth and discusses the possible application to TFTs with high speed operation.

The surface morphology and roughness of (100) P-doped ZnTe homoepitaxial layers grown by horizontal MOVPE using tris-dimethylaminophosphorus have been investigated as a function of substrate temperature under two different source transport rate conditions together with the photoluminescence property. The surface is marked by a dense ridging when the growth is limited by reaction-kinetics on the grown surface, whereas the surfaces of the layers grown in the mass-transport limited regime show morphology consisted of a series of hillocks, independent of the transport rate. The growth condition close to the transition part between the mass-transport and the surface-kinetics regimes provide an optimum growth not only for achieving a minimum surface roughness, but also for a better photoluminescence property of the as-grown P-doped ZnTe layer.

ZnS:Mn/ZnS core/shell nanoparticles were pre-synthesized by microemulsions technique. To prepare water-soluble and biocompatible nanoparticles, thioglycolic acid was directly added into the same reverse microemulsion system to modify the surface of ZnS:Mn/ZnS nanoparticles. The functionalized ZnS:Mn/ZnS nanoparticles were coupled with carboxyl and revealed farther luminescence enhancement at 600nm. The experiment results indicated that passivating of the organic molecules and the polynuclear complex of Zinc may be the possible mechanism leading to enhancement of luminescence.

The experiment about ramie fabrics processed by oxygen plasma was introduced. The mass spectrum of residual gas was measured by QMS, and quantities of hydrogen, carbon, oxygen and its compounds was observed from vacuum residual gas. The microcosmic characteristic of ramie treated by oxygen plasma show that the surface of the ramie fibre was effectively eroded by energetic particle and active molecules. It can be obviously seen from X-Ray diffraction analysis that the crystalline-indices of ramie fibre were slightly reduced after processing in oxygen plasma. Experiment results reveal that, with the increase of the processing time and power, the physical chemical properties such as wettability and dyeability were obviously improved.

In this paper, a thin amorphous hydrogenated carbon films were deposited on polyethylene terephthalate (PET) by means of capacitive coupled RF plasma-enhanced chemical vapor deposition (PECVD) using a mixture of CH₄ with Ar gas as a source. The chemical composition of the deposited films were analyzed by fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), laser Roman spectroscopy(LRS). And the microgram of the film was detected atomic force microscopy (AFM). The barrier properties were examined by water vapour permeation. The results show that the barrier performance of water vapor permeation in PET coated by hydrogenated carbon film was decreased from 86.16 (g/m²d) to 10.68 (g/m²d) in experiments.

The structural properties of B-O and O-implanted diamond films are investigated by using X-ray diffraction (XRD) and Raman spectrum. The results show that a sharp (111) peak of diamond can be found in XRD pattern after annealing under higher temperature, indicating the damaged diamond lattice produced by ion implantation has been restored. The calculated grain size of B-O co-implanted diamond films is smaller than that of O-implanted diamond under 1000 °C annealing, implying the introduction of boron into O-implanted diamond can hinder the grain growth under high temperature annealing. Raman measurements show that higher temperature annealing can recover the damaged lattice.

Multiferroic double-layer CoFe₂O₄-Pb(Zr_0.53Ti_0.47)O₃ (PZT) composite films have been fabricated by the hybrid process: pulsed-laser deposition (PLD) and sol-gel method. The CoFe₂O₄ (CFO) layer with different thicknesses was deposited on the substrates by PLD, and then the PZT layer was prepared on the top of the CFO layer by the sol-gel process. X-ray diffraction shows that there are no other phases but spinel CFO and perovskite PZT phases in the films. It is observed that the composite films demonstrate good ferroelectric and magnetic properties simultaneously. The composite films for the CFO layer of 120 nm are found to have the best ferroelectric property with the enhanced ferromagnetization.

In this paper, ZnO thin films with a polycrystalline preferential orientation and low surface roughness were successively achieved on Si (100) substrate by RF magnetron sputtering techniques under optimized experimental parameters. In our sputtered samples, the average grain size is around 15~23 nm calculated from Scherrer Formula, and transmittance in visible range was over 80% measured by spectrophotometer, d₃₃ equal to 27.5 pV/m measured by Piezoelectric Force Microscopy (PFM), surface roughness is below 3.00 nm and a good (002) plane orientation growth observed from XRD patterns. All the excellence properties of the ZnO thin films we acquired signal them are promising materials to be applied in electronic devices.

A series of 0.6BiFeO₃-0.4PbTiO₃ (BFO-PT) thin films were fabricated by sol-gel technique with sol concentrations varying from 0.2M to 0.4M. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized to characterize the structure and morphology of the BFO-PT films. The crystallinity of the films is improved with increasing the BFO-PT sol concentration. The dielectric properties and leakage current density of BFO-PT films were measured. The dielectric constants of all films are reasonably stable and the dielectric losses are below 5%. Considerably lower leakage current density is obtained in our sol-gel films.

Na⁺-doped ZnO thin films (Zn_1-xNa_xO, x=0-0.20) were prepared on Si<100> substrate by sol-gel method using zinc acetate and sodium carbonate as starting materials. The electrical properties, including the conducting type and the carrier concentration, as well as the optical properties of the so-obtained films were investigated by four-point probe van der Pauw method and photoluminescence (PL) spectroscopy. After doping Na⁺, the conductive type of ZnO films changed to p from n-type, indicating that Na⁺ can act as an acceptor to occupy the Zn²⁺ sites in ZnO lattice. The resistivity, Hall mobility, and the hole concentration of the film with x=0.10 were 75.7 Ω•cm, 2.1 cm²/V s and 2.955×10¹⁶/cm³, respectively. The PL results showed that there were a narrow near-band-edge (NBE) emission line and a broad deep-level (DL) emission for all the films with and without Na⁺ dopants. A slight blue-shift from about 383nm to 380nm of NBE line was observed for the films after doping Na⁺.

Homoepitaxial growth of 4H-SiC on off-oriented Si-face (0001) 4H-SiC substrates is performed at 1580°C, 100 mbar with rotation based on horizontal low-pressure hot-wall CVD (LP-HW-CVD) system to get high quality 4H-SiC epilayers. The surface morphologies and structural and optical properties of 4H-SiC epilayers are characterized with SEM, AFM, XRD and C-V measurement. By testing, the 4H-SiC epitaxial layer has a good crystalline structure and mirror-like surface with few surface defects. N type 4H-SiC epilayers are obtained by in-situ doping of N2. The Uniformity of doping concentration have been tested below 5%.

As the thickness of silicon solar cells becomes thinner, the cells are susceptible to bow because of the metallization of metal and semiconductor on the front and rear contact. In this work, the thickness impacts of aluminum and silicon on bow of the solar cell have been investigated with the perspective of deformation and strain.

The BSF of mono-crystal silicon cell is studied in this paper. It simply states the principle and formation process of BSF, and studies the evenness of BSF. In the experiment, we analyze BSF formed by taking different sintering temperature, heating rate and setting different time, develop by chemical reagent and observe at high magnification scope, analyze and get the optimal parameters of forming even BSF and further improve conversion efficiency of silicon chips.

Copper phthalocyanine (CuPc) is an important versatile organic material. It has attracted more and more attention because of its unusual stability and photoelectric properties. Copper phthalocyanine (CuPc) films, grown by vacuum sublimation, were characterized with X ray diffraction (XRD), Raman and UV-VIS spectrometry. CuPc/Aluminum (Al) Schottky solar cells were studied by varying the thickness of the CuPc layer from 30 nm to 130 nm. Optimum current density-voltage characteristics of ITO/CuPc/Al was obtained for 110 nm thick CuPc layer, which revealed the Short circuit current densities of 0.086 mA/cm² and the Open circuit voltages of 300 mV. Bathocuproine (BCP), tris (8-hydroxyquinolato) aluminum and LiF were used respectively as buffer layer to discuss their influences on the electrical characteristics of ITO/CuPc/Al Schottky solar cells. It was found that the insertion of a thin buffer layer would improve the performance except LiF.

Rapid thermal annealing effects on GaNAs/GaAs epilayer with about 1.0% N are experimentally analyzed. Both the as-grown and annealed samples are studied by photoluminescence at different temperature (11K~290K). Exciton localization and delocalization are investigated in detail. It exhibits quite different optical properties for the localized and delocalized excitons before and after annealing, this is attributed to the nitrogen reorganization inside the GaNAs layer, which homogenizes initial nitrogen composition fluctuations present in the as-grown alloy.

The Al-doped ZnO (AZO) films were deposited on the glass substrates by RF magnetron sputtering. After the deposition, the films were annealed in N₂ at several temperatures from 500°C to 800°C for 60 minutes respectively. The crystal structures of the AZO films were characterized and analyzed by X-ray diffraction. The surface morphologies of the films were observed by SEM. The transmission spectra of the films were measured using a spectrophotometer within the range from 200 to 800 nm at room temperature. The results indicate each of the films has a preferential c-axis orientation and the grain size increases with annealing temperature increasing. All the films exhibit a high transmittance in visible region and have sharp ultraviolet absorption characteristics.

This paper reports mechanical properties of P-doped hydrogenated nanocrystalline silicon (nc-Si:H) films prepared by PECVD in different conditions. The basic mechanical properties of nanocrystalline silicon thin films are evaluated from load, hardness and modulus curves using a nanoindentation instrument. The effect of P-doping rate and types of substrates on mechanical properties is discussed. It is indicated that proper phosphorus-doped nanocrystalline silicon films have lower carrying capacity, but they hold ideal interface combination strength and lower surface roughness; Nanocrystalline silicon thin films on glass substrates have better distortion coordination and film-substrate bonding strength compared to films on silicon substrates. In addition, it is also expected that the thickness of thin films can be roughly estimated by the first obvious step's position on the Load-depth curves.

Li₂B₄O₇ thin films were fabricated by screen-painting method on graphite substrates, and annealed at 300°C, 500°C, 600°C and 800°C for 3 hours, respectively. X-ray diffraction analyses show that the crystallinity of the films depends on the annealing temperature. The X-ray diffraction reflections of films become stronger after annealed at 300°C while a strong peak of graphite substrate appears. The XRD reflections of Li₂B₄O₇ layers broaden and weaken when annealed at 500°C-600°C.When the sample was annealed at 800°C, the XRD peaks of films become sharper and stronger again. These results indicate that the optimum annealing temperature for Li₂B₄O₇ thin films is 300°C or above 600°C. The SEM observations shows that the grain size is larger after annealed at 300°C. We also studied the optical absorption properties of the Li₂B₄O₇ films by the UV-VIS analysis.

In this paper, size dependence of tunneling magneto resistance (TMR) in nano particle arrays was studied with Monte Carlo simulation and resistor network model. When the electrode was applied along the X-axis, TMR increased as the length LJ increasing and then decreased in particle arrays, while TMR decreased with increasing length LJ as the electrode was along the Y-axis.

(Ba,Sr)TiO₃ (BST) thin films were deposited on the conducting perovskite LaNiO₃ electrode by radio-frequency (rf) magnetron sputtering technique. To investigate the crystalline of BST films, the substrate temperatures (T_d) in the range of 100°C-700°C were applied. The transition from amorphous phase to polycrystalline phase for the films occurred at low growth temperature 300°C. When the growth temperature approached 500°C, highly (h00)-oriented films were obtained. The relative dielectric constant (ε_r) increased rapidly with enhancing growth temperature because of improved crystallinity, and showed slowly increase above 500°C. In addition, the capacitance-voltage characteristics were studied with various growth temperatures. The tunability increased largely with good crystallinity. This can be attributed to increased dielectric constants.

A soluble partly linked PPV derivative of ZnPc (zinc phthalocyanine) and PPV (poly-phenylene vinylene) was synthesized (ZnPc-PPV) and characterized by electronic absorption and fluorescence spectrum. ZnPc-PPV exhibits high solubility and excellent film-forming property. The absorption spectra of ZnPc-PPV show intense absorption bands at 320 nm and 680 nm, which come from the characteristic absorption bands of Poly (α-hydroxyl-p-phenyl-acetyl) and ZnPc, respectively. The current-voltage characteristics of ZnPc-PPV blended with TAZnPc (ZnPc-PPV/TAZnPc) films under irradiation was 4.45 times higher than that in the dark.

Ordered mesoporous titania thin films have been grown on Si and ITO substrates by evaporation-induced self-assembly (EISA) progress. The films have well-organized honeycomb structures and consisted of anatase nanocrystallites according to the results of HRTEM. Between the regions of wavelength from 400 nm to 1250 nm, the simulation data of the refractive index coefficient (n) is decreased with the wavelength increasing. In contrast, the simulation of the extinction coefficient (k) is decreased quickly before the wavelength of 700 nm, and it is enhanced gradually with the wavelength increasing after the extreme value at about 700 nm. Simulation of n and k of mesoporous TiO₂ multilayer films from the data of transmission spectra are helpful to remedy the lack of spectroscopic ellipsometry measurement, especially in the regions of weak absorbance.

The structure, electrical and optical properties of nano-crystalline diamond (NCD) films deposited by hot-filament chemical vapor deposition (HFCVD) method, are reported. The influence of the carbon concentration during the film deposition on the Raman scattering, optical gap, optical constants (n and k) and dark-current is investigated. Under a higher carbon concentration during deposition, the NCD film obtained with a smaller grain size, has a lower optical gap, refractive index and electrical resistivity. These changes with the carbon concentration are attributed to the high amount of sp² bonded carbons and other non-diamond phase, which is confirmed by Raman scattering measurements.

Nanocrystalline diamond (NCD) films have been deposited by hot filament chemical vapour deposition (HFCVD) from acetone/hydrogen gas mixtures on a variety of substrates such as silicon wafers and polycrystalline diamond. The influence of the chemical nature of the substrate, the roughness, and the pretreatment of the substrates on the nucleation and the bulk structure of the NCD films are investigated. By means of X-ray diffraction (XRD) and Raman spectroscopy it is shown that the bulk properties of the films are not affected by the status of the substrate although these have a strong influence on the nucleation behaviour.

Diamond films with various grain sizes are grown on silicon substrates by hot-filament chemical vapor deposition method. Scanning electron microscopy (SEM) measurement shows that the films consist of diamond grain with an average crystallite size of 1.4-0.1μm. The optical and structural properties of diamond films are investigated by spectroscopic phase modulated ellipsometer in the energy range of 0.8-1.5eV. A three-layer model, Si/diamond film/diamond film + void/, is applied to diamond film based on Bruggeman effective-medium approximation and New Amorphous dispersion formula which is a rewrite of Forouhi-Bloomer formulation. By fitting spectroscopic characteristics (Ψ,Δ) with Levenberg-Marquardt regression algorithm, the energy band gap and refractive index are obtained, along with the film thickness, bulk void fraction and roughness layer. The study indicates that both energy band gap and refractive index decrease when grain size reduces due to the raise of disorder sp² bonded carbon. The result on the Raman scattering measurement is consistent with the fitting result of spectroscopic ellipsometer.

Uncrystallized copper indium disulphide (CuInS₂) thin films have been deposited on ITO glass by chemical bath deposition (CBD) in acid conditions. Then polycrystalline CuInS₂ films were obtained after sulfuration in sulfur atmosphere at 300°C, 350°C, 400°C and 450°C for 1.5 hours respectively. The films have been characterized by X-Ray diffraction (XRD), scanning electronic microscopy (SEM), precision surface profiler, energy dispersive X-ray analysis (EDX) and Hall effect measurement system. The results show that with the raising of heat treatment temperature the crystal degree and electrical property of the film are improved. Our work demonstrates the chemical bath deposition in acid conditions is a promising method for deposition of CuInS₂ thin films for solar cells.

Multilayered (Pb_1-xSr_x)TiO₃ thin films consisted of uniform PST(x) and sandwich-like compositionally graded PST80- 60-80 were fabricated on Pt/Ti/SiO₂/Si substrates by coating the solutions with different Sr contents(60≤Sr(mol%)≤80), respectively. Their structural and dielectric properties were investigated. Both uniform and compositionally graded films crystallized into a perovskite structure with no second phase found after post-deposition annealing. Among uniform films, the PST60 films showed the highest dielectric constant and tunability, but low figure of merit(FOM) due to relatively higher dielectric loss. For the sake of bringing down the dielectric loss, the PST60 thin films were sandwiched by PST80 thin layer, resulting in a decrease in dielectric loss and slight decrease in tunability. Besides the improvement of FOM, the temperature stability of graded PST80-60-80 thin films was also enhanced.

The Cu(In_1-xGa_x)Se₂ (CIGS) thin films were prepared by stacked elemental layers (SEL) method via vacuum evaporation. X-ray diffraction (XRD) analysis showed that the films were consisted of chalcopyrite CIGS phase. Scanning electronic microscopy indicated that the film surface was compact and the grain size was about 1μm. It was found that CIGS film with preparation sequence Ga/In/Cu/Se was of best crystalline quality. Besides, adding Ga greatly improved the crystallinity for all sequences compared with CIS films at the same annealing temperature.

The influence of DC Joule heating treatment on the longitudinally driven giant magneto-impedance (GMI)effect of Fe₃₆Co₃₆Nb₄Si_4.8B_19.2 ribbons was studied, and the GMI effect responded sensitively (the sensitivity was as high as 2440.2%/A•m^-1) to weak magnetic field was detected after annealed at current density of 3.2×10⁷A/m² for 600-second. The experimental results showed that the sensitivity is closely related to annealing current density, driven current frequency and eroded thickness.

Transparent luminescent films have been believed to have the potential applications in high spatial resolution X-ray imaging system. However, it is usually restricted by the thickness of the film. Instead of alkoxide, GdTaO₄:Eu³⁺ film with a thickness of about 0.8 μm was prepared from an inorganic salt-2-methoxyethanol solution containing polyvinylpyrrolidone (PVP) as an additive via single-step spin coating. The whole process was carried out without inert atmosphere which is necessary for alkoxides. The fired film is optically transparent and crack-free, and exhibits a strong luminescence at 611 nm under X-ray excitation.

ST-401 plastic scintillation films were prepared by spin coating. The self-supporting films were obtained and they displayed a satisfactory appearance in terms of uniformity and transparence. The relationship between photoluminescence (PL) property and film thickness was presented and the influence of preheat temperature of coating solution on PL intensity of the film was discussed in detail. The results indicated that the PL intensity increased whereas PL intensity ratio of PTP to POPOP decreases with the increase of the film thickness. PL intensity of the film at 423 nm was improved remarkably by heating the coating solution, which makes ST-401 films have a promising application in the detection of low-intensity pulsed fission neutron flux.

The linear electro-optic (Pockels) effect of wurtzite gallium nitride (GaN) films and six-period GaN/Al_xGa_1-xN superlattices with different quantum structures were demonstrated by a polarization-maintaining fiber-optical Mach-Zehnder interferometer system with an incident light wavelength of 1.55μm. The samples were prepared on (0001) sapphire substrate by low-temperature metalorganic chemical vapor deposition (MOCVD). The measured coefficients of the GaN/Al_xGa_1-xN superlattices are much larger than those of bulk material. Taking advantage of the strong field localization due to resonances, GaN/Al_xGa_1-xN SL can be proposed to engineer the nonlinear responses.

Undoped and In-doped SrIn_xTi_1-xO₃(x=0, 0.1, 0.2) films have been deposited on Si(100) and quartz substrates by oxygen plasma-assisted pulsed laser deposition (PLD). Effects of indium doping on the crystallinity and the optical energy band gap of SrTiO₃ (STO) films were investigated. Results indicate that undoped STO film is of rather good crystallinity and low defects concentration. However indium doping deteriorates the crystallinity of the STO film, and results in the roughening of the film surface. Moreover the a-axis length monotonically increases when increasing In content. For all the films, the average transmission in the visible wavelength region (λ=400-800nm) is over 75%. The optical energy band gap of STO thin films, measured from transmittance spectra, changes from 3.67eV to 3.93eV by indium doping.

Fluorescent pyrrole nanoparticles were first synthesized through plasma polymerization under atmospheric pressure and room temperature. The spherical polypyrrole nanoparticles with a diameter of 100-200 nm are uniformly distributed. FTIR was used to investigate the structure of atmospheric pressure plasma polymerized polypyrrole nanoparticles (AP-PPy nanoparticles). The result indicates that the nanoparticles keep a better reservation of the pyrrole structure. The effect of power on the optical property of AP-PPy nanoparticles was analysised with UV-Visble absorption and PL spectra. Polarization induced coplanarization of pyrrole and high level of chain stock during the nucleation and growth of nanoparticles. These lead to a better conjugation of chains, and avoid the aggregation quench. Thus polypyrrole nanoparticles exhibit a strong fluorescence emission at the range of 415nm to 450nm with different power. This technology will help to the realization of practical optoelectronic nanodevice applications of fluorescent polymeric nanoparticles.

In this work, La_0.7Sr_0.3MnO₃ (LSMO) thin films have been prepared on Pt/Ti/SiO₂/Si substrates at different substrate temperatures by pulsed laser deposition (PLD) method. Nonlinear current-voltage (I-V) behavior and the electric-pulse-induced resistance change were observed in all Ag/LSMO/Pt heterostructures. Resistive switching properties exhibit very strong dependences on the film crystalline qualities. Also, models for interpreting the results were also proposed.

The dielectric properties of Ba_0.6Sr_0.4TiO₃ (BST) thin films were greatly affected by interfacial layers between the electrodes and BST thin films. Our previous work shows that the dielectric loss of the BST system can be decreased by an excess of Ti contents. In this paper, TiO₂ buffer layers were grown between BST thin films and the Pt coated silicon substrate, which are expected to improve the interfacial conditions by providing a certain amount of titanium. Both BST and TiO₂ films were prepared by pulsed laser deposition. Different substrate temperatures of 550°C, 600°C, 650°C, 700°C and different oxygen pressures of 1mTorr, 10mTorr, and 100mTorr were used for the deposition of TiO₂ buffer layers. XRD pattern shows that all the samples have crystallized into the perovskite structure and the (110) peaks become sharper with increasing substrate temperature, indicating better crystallization along this direction. The increased tunability and lower loss of BST thin films with TiO₂ buffer layers prepared at the optimized temperature and oxygen pressure achieve about 45.9% and 0.01 at the field of 200kV/cm and 1 MHz. The figure of merit of BST thin films is significantly improved to 45.9 upon using TiO₂ buffer layers, which is only about 18.2 for BST thin films prepared directly on the substrates. Our results indicate that TiO₂ buffered BST thin films are expected to have better dielectric and tunable properties.

Good electrode materials play an important part in rechargeable Li batteries. In this paper, safe and inexpensive vanadium pentoxide (V₂O₅) aerogel materials were used as cathode materials. We discussed preparation of the films and lithium ion diffusion at the interface between the cathode and electrolyte by potential-step current transient technique and digital simulations. The results showed that diffusion coefficient (D_Li) of the V₂O₅ aerogel film was 9.18×10^-14cm²/s and exchange current was 12.5×10^-6A at potential step 3.6~3.5V_Li/Li+.

Tin oxide nano-films with different grain-diameter have been synthesized by the modified sol-gel method, used tin chloride dihydrate (SnCl₂•2H₂O) as main materials and ethanol as solvent. After magnetic agitation and ageing, tin oxide (SnO₂) thin films were prepared on silicon substrates by spin-coat process and then annealed at different temperature in oxygen atmosphere. The obtained samples are polycrystalline films with rutile structure and have preferred orientation of (110) direction. The crystal structure, the morphology, and the optical property of the thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared Spectrometer (FT-IR).

Using high accurate infrared spectroscopic ellipsometry, the infrared dielectric constants of BaTiO₃ ultrathin films are obtained in the temperature ranging from 20 to 150°C, which were deposited on Pt-Ti-SiO₂-Si substrate by radio frequency magnetron sputtering. The high frequency dielectric function of the BaTiO₃ ultrathin films shows the temperature dependence from the tetragonal to the cubic phase transition. The results suggest that the temperature dependence of the BaTiO₃ ultrathin films' infrared dielectric properties should be considered in the technological applications and theoretical investigations.

Ferroelectric Pb(Zr_0.53Ti_0.47)O₃ (PZT) thin films were grown on silicon substrates by modified So1-Gel method using C₄H₆O₄Pb•3H₂O, ZrO(NO₃)₂•2H₂O and Ti(OC₄H₉) as raw materials. PbTiO₃ (PT) thin film was introduced as buffer layer. The microstructures of PZT thin films were characterized by XRD and SEM. Electrical properties such as C-V and leakage current characteristics of the films was investigated. The results show that PT buffer layer was helpful to improve the dielectric and ferroelectric properties of PZT thin films. PT buffer layer prevented the interface reaction and reduced the leakage current density of PZT/PT/Si structure about 10^-2 compared with that of PZT/Si structure.

Tin sulfide (SnS) thin films for solar cells were deposited by vacuum evaporation at different substrate temperatures in a range of 20~200°C. The films were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM) for structural analysis. The electrical and optical properties were also investigated. Under the substrate temperature of 150°C, the obtained SnS thin film was in orthorhombic structure with a grain size of 0.5 μm and composition of Sn:S =1:1. The measurement results from hot probe method showed p-type nature for the deposited films. Dark-conductivity and photo-conductivity were 0.01Ω^-1•cm^-1 and 0.08Ω^-1•cm^-1, respectively. The optical band-gap energy of the films was estimated to be 1.402 eV.

Tin sulfide (SnS) is one of promising candidate materials for low-cost thin film solar cells because of its high absorption coefficient and suitable band-gap. The aim of this paper is to study the properties of doped-SnS thin films prepared by vacuum evaporation. Sb₂O₃ was used as the doping source (the weight ratio of Sb₂O₃ to SnS in the range from 0.1% to 0.8%). And then the Sb₂O₃-doped SnS thin films were annealed in the hydrogen atmosphere at different temperatures and times. The structure of all the samples was characterized by X-ray diffraction (XRD). The electrical properties of SnS thin films were investigated as well. From the results, the optimum doping content of Sb₂O₃ was 0.2% in weight, and the resistivity of the doped-SnS film was 42Ω•cm while that of the pure-SnS film was 99Ω•cm. In addition, the film resistivity of Sb₂O₃-doped SnS film decreased to 24Ω•cm with the best annealing conditions of 400°C and 3 hours.

Fe-based nanostructures have been synthesized by two different template-directed methods: electrochemical and chemical deposition. The products exhibit unique magnetic properties. The two approaches are firstly compared with each other through the characterization of the crystalline structure, morphology and magnetic properties of the as-prepared products using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), energy dispersive analysis (EDS) and physics property measurement system (PPMS). The results show that the nanowires can be obtained by electrochemical deposition while the nanotubes obtained by chemical deposition. The growth mechanism is also briefly discussed.

The free-standing diamond films with a smooth and high quality nucleation side were prepared by hot filament chemical vapor deposition (HFCVD) method. The nucleation side of the films had a mean surface roughness of 1.6nm.AlN films were then deposited on the nucleation side of the above diamond films by radio-frequency (RF) reactive magnetron sputtering method. The structure characteristics of AlN films deposited under different working pressure (p), sputtering power (w) and sputtering plasma composition were studied. The optimized parameters for the growth of high c-axis orientation AlN films were obtained: p=0.2Pa,w=600w and Ar/N₂=3:1.Surface morphologies of AlN films deposited under these parameter, tested by means of atomic force microscope (AFM), showed that the mean surface roughness was about 4.1nm.It also had a strong c-axis orientation structure investigated by X-ray diffraction (XRD). All results above suggested that the AlN/diamond structure prepared in this work was ideal for the application of high frequency surface acoustic wave devices (SAW) device.

Nanocrystalline diamond(NCD) films with a mean surface roughness of 23.8 nm were grown on silicon substrates in a hot filament chemical vapor deposition(HFCVD) system. Then, Zn_1-xLi_xO (x=0, 0.05, 0.10, 0.15) films were deposited on these NCD films by radio-frequency(RF) reactive magnetron sputtering method. When x was 0.1, the Li-doped ZnO film had a larger resistivity more than 10⁸Ω•cm obtained from Hall effect measurement. All the Zn_1-xLi_xO films had a strong c-axis orientation structure determined by X-ray diffraction (XRD). The above results suggested that the Li-doped ZnO film/NCD structure prepared in this work was attractive for the application of high frequency surface acoustic wave (SAW) devices.

A hot filament chemical vapor deposition (HFCVD) apparatus, combined with a cyro-cooled superconductor magnet, were recently developed. Nanocrystalline diamond (NCD) films were prepared by above HFCVD apparatus either with or without high magnetic field. Surface morphologies of these films were characterized by means of atomic force microscope (AFM). The results indicated that the mean surface roughness and grain size of these films decreased when the magnetic field varied from 0T to 4T. From Raman scattering measurement, all films prepared either with or without high magnetic field exhibit NCD features. These NCD features of the sample prepared with 4T magnetic field was obviously pronounced. The structure of these films was also investigated by X-ray diffraction (XRD).

We report on a new nanopore formation technique by utilizing SiC/Si(100) heteroepitaxial growth. The SiC growth onto Silicon-On-Insulator substrates was carried out by CH₃SiH₃ supersonic jet chemical vapor deposition. Inverse pyramidal pits surrounded by {111} facets were created in the top Si layer during the SiC heteroepitaxial growth. Randomly distributed nanopores with the diameter of ~10 nm were obtained in the top ~180 nm thick Si layer by removing the buried oxide layer under the pits. It was found that the oxide patterns on the top Si layer were effective for the site-control of the nanopore formation.

A silicon-oxide-based porous methyl material such as a porous SiOCH has been investigated as a Low-K film for post 45nm node generation. However, low young modulus of porous Low-K films is serious issues in Cu/Low-K interconnection. We have investigated Low-K material of Boron Nitride containing methyl (Methyl Boron Nitride) by using Tris-di-methyl-amino-boron (TMAB) gas. This paper reports on properties of a Methyl BN film by TMAB. We have succeeded in Low-K material (K value:2.2) with Young modulus >26GPa.

The quasi-periodical quaternary ferroelectric Bragg reflectors were fabricated by using precursor solution with PEG additive. For PZT, both PEG and PVP are suitable polymers in fabrication of periodical structures based on one single chemical solution, while for BST the optical performance of the BST multilayers derived from the solution containing PVP is better than that of the BST multilayers prepared using the PEG-containing solution. One or two defect layers were inserted into the multilayers. The single cavity BST multilayer shows well-defined resonant cavity mode occurring in the reflection stop band while the BST multilayer with double cavities exhibit two coupled cavity modes on the high reflection band.

The smooth relaxed SiGe films were fabricated on Si(001) substrate using 30nm thick buffer layers by molecular beam epitaxial (MBE). The buffer layers were fabricated as followings: first deposited 20nm thick SiGe alloy layer at 550°C, then 10nm Si buffer was deposited at 400°C. After the buffers were finished, the top SiGe layer with the thickness of 200nm was deposited at 500°C. The deposition quality, thin film structure and residual strain in the film were characterized by high-resolution X-ray diffraction (HRXRD). We found that the surface morphology and crystal quality of SiGe thin film can be improved obviously. It was shown that SiGe top layer was relaxed and smooth by comparing the measured and simulated (004) rocking curves. The peak range and relative position of the SiGe epilayer with respect to the Si substrate in high-resolution reciprocal space map(HRRSM) described clearly the high crystal quality and the strains relaxation. The surface morphologies of thin films were also observed by atomic force microscopy (AFM). The surface is very smooth with RMS less than 7 Å.

SrTiO₃ (STO) thin films were grown on Si(100) substrates by RF magnetron sputtering. The substrate temperature was found to be a crucial parameter to obtain the highly (h00) oriented growth. At the substrate temperature of 700 °C, STO thin films with the (h00)-orientation parameter (α_h00) of more than 93% were realized. Using vitreous silica as the substrate, the optical properties of STO thin film prepared at 700 °C were investigated by transmittance measurements. The fitting method was used to calculate the refractive index and the film thickness from the transparent region of the transmittance spectra. The dispersion of the refractive index was studied by considering a single electronic oscillator model. According to Tauc's law, the band gap of the film was found to be about 3.62 eV.

An optimal energy interval in ion-assisted deposition of high crystalline films is predicted in the modeling of ion impacting on surface. The result is in good agreement with the presented experiments. The possible application of the evaluation of ion role for the fabrication of potential thin film materials is expected.

By using low cost, low-temperature hydrothermal approach and spin-coating technique, well-aligned ZnO nanorods have been successfully prepared on ITO substrates. The ITO substrate was pre-patterned with ZnO particles as a seed layer for the subsequent nucleic hybridization. The intuitionistic crystallinity of oriented ZnO nanorod array was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. It is shown that the preferred orientation growth of the wurtzite structure along (002) plane is easily obtained with the approach. The size of the ZnO nanorods has been found to be dramatically dependent on the concentration of zinc content in the solution.

The effects of working pressure on the properties of 355nm Al₂O₃/MgF₂ HR coatings were investigated. A series of samples were deposited by electron beam evaporation using the same deposition process at different working pressure. Transmittance of the HR coatings was measured by Lambda 900 spectrometer. Structure of the samples had been characterized by X-ray diffraction (XRD).The stress was measured by viewing the substrate deformation before and after coatings deposition using an optical interferometer, the stress results range from 223MPa to 315MPa. Laser-induced damage threshold (LIDT) was measured by a 351 nm Nd:YAG laser with a pulse width of 7 ns, the LIDT results range from 2.69 J/cm² to 11.03 J/cm² with the working pressure changing. It was found that working pressure has important effects on the absorption, stress and LIDT of 355nm Al₂O₃/MgF₂ HR coatings. (351nm, 7ns).The working pressure was no clear effect on the crystalline structure of the HR coatings.

In this paper, the defects in hexagonal GaN epitaxial layers grown on (0001) sapphire (Al₂O₃) substrates by HVPE with a horizontal tube reactor had been studied. The GaN epitaxial layers were etched by means of defect-selective etching (Orthodox etching in molten KOH). The samples were characterized by Scanning Electron Microscopy (SEM) and Cathodoluminescence spectra (CL). From surface morphology and cross-sectional images, the defects could be divided into various types: cracks, low angle grain boundary (LAGB), nano-pipes and dislocations. These different defects were discussed. The cracks were proposed as related to the strain. And the strain could not only come from the lattice mismatch and thermal mismatch between sapphire and GaN layer in their interface, but also from the HVPE growth process. It was found that these screw, mixed and edge type dislocations formed small hexagonal pits after etching. Some pits would be observed in the area near LAGB. Additionally, by CL mapping technique, some non-radiative recombination centers without surface terminations could be probed optically.

PTFE nano-crystallines with different morphology and crystal structures were rapidly formed by an Atmospheric Plasma Polymerization at room temperature without any catalysts or templates. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) results indicated single crystal phase of the nano-crystallines. Other characterization methods, such as Polarization optical micrographs of the nanocrystallines at high temperatures showed their higher thermal stability compared to the PTFE bulk polymers. The atmospheric oriented plasma polymerization can serve as a common method for nanofabrication of many other single crystalline polymer systems.

Plasma polymerization of fluorocarbon was processed through dielectric barrier discharge (DBD). A thin hydrophobic film packed with nano-particulate structure was obtained on cotton fabric surface. The contact angle of the water and 1-bromonaphthalene on coated cotton fabric was 133° and 124° separately. The surface morphology of the coating was observed through SEM (Scanning Electronic Microscope). It was found that cotton fabric surface was tightly adhered to a thin film packed by nano-particles from 10nm to 200nm. This process showed potential applications in continuous coating of textiles with functional nano-particulate polymers, but without changing their softness performance.

A simple and efficient technique for fabricating two-dimensional arrays of silicon nanotips by using electron beam lithography (EBL) and reactive ion etching (RIE) was reported. For the RIE processes, two kind of reactive gases, CHF₃ and SF₆, were used as plasma etching source for Si. The experiment results indicate that the reactive ion etching mechanism is different: the isotropic process for SF₆ and anisotropic for CHF₃. It is found that the mixed O₂/SF₆ plasma etching can improve the properties of profile and surface of Si nanotips. Under the condition of ratio ~15%, the 10 nm top size of Si nanotips was obtained.

A new criterion about substrate cleanliness level was established by an adhesion measurement for Al and Cu thin films deposited onto both Si and quartz glass substrates cleaned by various methods, such as swab scouring, ultraviolet light irradiation, and oxygen plasma ashing. The substrate surface contamination level was controlled by exposing the substrate itself to low vacuum impregnated with rotary pump oil mists. The new criterion about the substrate cleanliness level was somewhat different from the water wettability one. In the case of the UV irradiation, adhesion strength increased with exposure time, and then a constant maximum value was kept. On the other hand, the excess oxygen plasma ashing resulted in adhesion degradation due to the Si surface oxidation.

By direct current electrodeposition technique combined with the anodic aluminum oxide films, Ni-based nano-arrays were successfully performed. The structure was studied by X-ray diffraction and high-resolution transmission electron microscopy with selected-area electron diffraction. Energy dispersive spectroscopy was used to prove the composition of the prepared nanowires. The magnetic property curves of Ni-based nano-arrays were measured by a physical property measurement system. According to electrochemical analysis, the growth kinetics of the nanowires was studied by determining the relationship between the current and time under different parameters, such as electrolyte temperature and electrodeposition voltage.

Hydrophobic and hydrophilic films with titanium oxide inside were grown by radio frequency plasma enhanced chemical vapor deposition (RF--PECVD) on glass substrates. Bias voltage was used as an assistant for the deposition process. And a comparison was made between with and without the bias voltage. Titanium tetraisopropoxide (TTIP-Ti (OC₃H₇)₄) was used as the precursor compound. Film wettability was tested by water contact angle measurement (CAM). The water contact angle (WAC) of the film deposited in plasma without biased voltage was greater than 145°, while the WAC of the film deposited in plasma with biased voltage was less than 30°. The morphology of the deposited films was observed by scanning electron microscope (SEM). It is found that the films grown without bias voltage were covered with lots of nano grain and pores, but the surface of the films deposition with bias voltage was much dense. The chemical structure and property of the deposited films were analyzed by Fourier-transformed infrared spectroscopy (FTIR), while the plasma phase was investigated by optical emission spectroscopy (OES).

In this paper, Fe_XAl_1-X films have been deposited on silicon substrates using electron beam evaporation, which have been not reported to prepare Fe_XAl_1-X films before. Subsequently, the films were annealed in vacuum better than 3×10^-4Pa for 1 hour at 100°C, 280°C, 330°C, 450°C and 500°C, respectively. Electrical resistivities of the samples were been measured by four point probe, and microstructures of the samples were characterized by X-ray diffraction(XRD). The results show that, the resistivity of films reduces gradually with increasing of the annealing temperature, and the structure of films can be improved after annealing. In addition, the resistivity of film reduces gradually with increasing thickness and comes closed to the that of bulk when the film thickness becomes thicker than 100nm.

Fe_xAl_1-x thin films had been prepared on Si (100) substrates by electron beam evaporation. The substrate temperature was varied from room temperature to 450°C at an interval of 100°C. The crystalline orientation of deposited Fe_xAl_1-x thin films had been characterized by X-ray diffraction (XRD) and the thickness was measured by Atomic profiler. The results show that the crystalline orientation of Fe_xAl_1-x thin films depends on the substrate temperature. The thin films are crystal at different substrate temperatures. The deposition rate becomes bigger from 30°C to 250°C and smaller from 250°C to 450°C. The surface morphology of deposited Fe_xAl_1-x thin films had been investigated by atomic force microscopy (AFM). The results show that the surface roughness increases with increasing the substrates temperature to 450°C.

Ferroelectric Pb(Zr_0.53Ti_0.47)O₃ (PZT) thin films were deposited on LaNiO₃ (LNO) buffered metal substrates by sol-gel method. The LNO buffer layer also prepared by sol-gel method serves as the template for growing PZT thin films with preferred orientation. The LNO sol is the precursor to prepare the LNO buffer layer. With the decreasing of the LNO sol concentration, the PZT films on LNO layer shows varying intensity of the XRD (100) and (110) orientation, as well as variation of the structural and dielectric properties. The PZT thin films with good dielectric properties can be obtained on LNO buffer layer with LNO-sol of 0.1mol/L.

The nanowire arrays containing two phases of CdTe and Te have been synthesized by direct-current (dc) electrodeposition in anodic alumina membrane (AAM) at room temperature. The results of transmission electron microscope (TEM) show the nanowire arrays have ordered diameters of about 60 nm, which corresponds to the pore size of the AAM template we used. The selected area electron diffraction photo shows the nanowire arrays have the mixture structure of single crystal and polycrystalline. The growth mechanism of the nanowire arrays is also suggested.

ZnO thin films with or without Al doping were grown on the glass substrates by sol-gel method and subsequently annealing treatments at high temperatures were performed to optimize films' morphologies and properties. The crystal structures of ZnO films were characterized by X-ray diffraction (XRD), and XRD spectra show a shift of (002) diffraction peak to the higher 2θ values with changing the Al-doping concentration. Optical transmittance spectrums exhibit a sharp absorption edge at around 380nm undergoing a blue shift induced by aluminum doping. An apparent particle size decreasing was displayed by scanning electron microscopy (SEM) images with the Al-doping concentration increasing.

Voltage-induced reflective changes of Pt/BLT/Si and Pt/STO/Si are investigated in visible and near infrared band. A theoretic calculation of inversion layer plasmons is set up. The most sensitive optical band and the voltage value interval causing fastest change rate are indicated. Some variance regularities are described, and this study provides the basically theoretical support for the application of an optical readout infrared imaging device: MFIS.

Manganese cobalt nickelate films (Mn_xCo_yNi_3-x-y)O₄ (MCN) are successfully prepared by chemical deposition method at a crystallization temperature of 600°C, which is greatly reduced from the traditional sintered temperature of ~1050 - 1200°C. From the XRD and AFM, we find the grain size of the MCN films increases from 20 to 60 nm with the annealing temperature increase from 600°C to 900°C.

Tin oxide thin films have been deposited on oxide silicon substrates using a RF magnetron sputtering process with various sputtering power. The crystal structures of the tin oxide thin films were characterized and analyzed by X-ray diffraction. The surface morphology of the films were observed by SEM. The electrochemical properties of the films were also tested by constant current charge and discharge cycle tests. The results of XRD indicate that all the films are crystalline. The results of SEM exhibit that the grain size of surface expands as sputtering power rises.

Based on the analysis of mechanism of silicon polishing, this paper discusses the influence of the final polishing slurry on polishing quality. The selection of components in the final polishing slurry is discussed. The abrasive of small size is used to reduce the surface roughness. The alkali without sodium ions is selected to reduce metal ions pollution. The relation between adsorption mechanism and the surfactant is analyzed. As a result, the nonsodium final polishing slurry with small particle size, high polishing rate and high quality is realized.

Vanadium oxide (VOx) thin films were deposited on different substrates by reactive DC magnetron sputtering. Silicon substrate, Si₃N₄/Si substrate, glass substrate, and α-Al₂O₃ substrate were adopted in experiments. Results revealed that the structural features of VOx thin films strongly depend on the substrates. Analysis of square resistance and its temperature dependence demonstrated that the crystal structure and the growth mode of VOx films play important roles in the film electrical properties. Experiments demonstrated that substrates have great influence on the growth mode and thermal resistance properties of VOx thin films.

The dependence of morphology and thermal resistance on the substrate temperature during the deposition of the vanadium oxide thin films (VOx) was studied. Atomic-force microscopy (AFM) analysis results revealed that the structural features of VOx thin films strongly depend on the substrate temperature. Analysis of square resistance and its temperature dependence demonstrated that the difference of morphology introduced by substrate temperature plays an important role on the electrical properties of the films. The width of the thermal resistance hysteresis loop was also observed varied with the substrate temperature.

This paper describes the properties of the homoepitaxial 4H-SiC layer, the fabrication and electrical parameters of Ti/4H-SiC Schottky barrier diode (SBD). The 4H-SiC epitaxial layers, grown on the commercially available 8°off-oriented Si-face(0001) single-crystal 4H-SiC wafers, have been performed at 1550~1600°C by using the step controlled epitaxy with low pressure chemical vapor deposition. X-ray diffraction measurement result indicates the single crystal nature of the epilayer, and Raman spectrum shows the typical 4H-SiC feature peaks. When the off-oriented angle of substrate is 8°, the epitaxial growth perfectly replicates the substrate's polytype. High quality 4H-SiC epilayer has been generated on the 4H-SiC substrate. Ti/4H-SiC SBDs with blocking voltage 1kV have been made on an undoped epilayer with 12um in thick and 3×10¹⁵cm^-3 in carrier density. The ideality factor n=1.16 and the effective barrier height φ_e=0.9V of the Ti/4H-SiC SBDs are measured with method of forward density-voltage (J-V). The diode rectification ratio of forward to reverse (defined at ±1V) is over 10⁷ at room temperature. By using B⁺ implantation, an amorphous layer as the edge termination is formed. The SBDs have on-state current density of 200A/cm² at a forward voltage drop of about 2V. The specific on-resistance for the rectifier is found to be as 6.6mΩ•cm².

Ge films have been deposited on Si (100) substrates with graded Si_1-xGe_x:C buffers by chemical vapor deposition (CVD) method. Based on the Auger electron spectroscopy result, a growth model for the buffers has been proposed, in which the buffers are thought to be composed of two layers. One is the Si_1-xGe_x:C epilayer due to the reaction of GeH₄, C₂H₄ and Si atoms diffusing up from the substrate, and the other is the Si_1-xGe_x layer due to the reaction of Si and Ge atoms diffusing down from the Si_1-xGe_x:C epilayer. The energy dispersive spectroscopy result indicates that Ge atoms diffuse further when the growth temperature is higher, demonstrating the growth model indirectly. With the graded buffers, epitaxial Ge films show the perfect crystalline quality, and the excellent transport property with the electron mobility approaching that of bulk Ge materials at the same doping level.

We investigate the growth of Mg doped Al_xGa_1-xN films grown by metal organic chemical vapor deposition (MOCVD). The high temperature AlN interlayer can improve the quality of films, reducing the density of dislocations. With the increase of Al composition, the quality of films dramatically decreases, and a large number of island-shaped crystal nuclei can be observed, for three-dimensional growth mode of Mg-doped Al_xGa_1-xN can not be transformed into two-dimensional mode easily. Both the increase of Al composition and Cp₂Mg flux can increase the density of screw dislocations. The increase of Cp₂Mg flux can considerably increase the density of edge dislocations, while the increasing Al composition has little impact on the density of edge dislocations. Finally, annealing at 900°C for 15 minutes after growth is the ideal annealing condition for obtaining p-type Al_0.2Ga_0.8N, with hole concentration of 1.0×10¹⁷ cm^-3.

The optical properties of the nano-ZnO thin films were studied, which were prepared by low temperature wet chemical-method combined with ultrasonic treatment. The thin film could emit the strong UV and blue light. The blue emission was caught by the interstitial zinc (Zn_i), which could be confirmed by Raman spectrum. The relationship of the optical properties and processing parameters was also discussed. The reaction temperature, the reaction time and the different molar ratios of Zn²⁺ to TEA could affect on the intensities of the UV emission and the blue emission of the ZnO thin film, respectively. The mechanism of the phenomena was brought forward by analyzing the FTIR spectrum.

We introduce a double source electron beam evaporation (DSEBET) technique in this paper. The refractive index coatings were fabricated on K9 glass substrate by adjusting the evaporation rates of two independent sources. The coatings, which were described by atomic force microscopy (AFM), show good compactness and homogeneity. The antireflective (AR) coatings were fabricated on Superluminescent Diodes (SLD) by DSEBET. The hybrid AR coatings on the facets of SLD were prepared in evaporation rates of 0.22nm/s and 0.75nm/s for silicon and silicon dioxide, respectively. The results of AFM and spectral performance of coated SLD show that DSEBET has a promising future in preparing the coatings on optoelectronic devices.

The present study focuses on the numerical study of 4H-SiC film deposition on a horizontally 4H-SiC substrate with H₂ as the carrier gas and C₃H₈ and SiH₄ as precursors in low pressure using a hot wall CVD reactor. The growth rate along the susceptor is calculated. The effect of inlet C/Si ratio on the growth rate is investigated. Among the reacting species C₂H₂, CH₃SiH₂SiH, Si and SiH₂ contribute most to growth.

Wurtzite structure ZnMgO thin films with the energy gap (E_g) of 4.2 eV were deposited by oxygen-plasma enhanced pulsed laser deposition (PEPLD) on quartz glass. Oxygen-plasma increases the Zn content in ZnMgO thin film, which induced the evolution from cubic to hexagonal structure. The effects of target-substrate (T-S) distance on the band gap and crystal quality of ZnMgO thin film deposited by PEPLD were studied by transmittance spectra and Raman. The band gap of ZnMgO increased from 3.84 eV to 4.03 eV and the crystal quality decrease gradually when the T-S distance decreased from 9 cm to 5 cm.

Using physical vapor deposition (PVD) method, the (cBN/nano-diamond)₃ multilayer film with phase purity, high hardness and low residual stress was synthesized on silicon substrates supported by a thick nano-diamond buffer. This method presented is characteristic with the direct cBN growth on diamond without soft, non-cubic BN interface layers; the synthesis of multilayer films with extraordinary adhesion to the substrates and higher hardness than a cBN single film, and the stress of the multilayer film can be reduced to only one forth of that of a cBN single film. These prime technological properties open the route to the mechanical exploitation of cBN films.

ZnO thin films were prepared by two methods .One was ion beam sputtering then annealing at 700°C in O₂, another was RF magnetron sputtering then annealing at 600°C in O₂. The structures, morphologies, and electrical resistivities of the ZnO films prepared by two methods were investigated and compared. The influences of two different methods on properties of ZnO thin film were studied by XRD, AFM and LCR HITESTER. Compared with RF magnetron sputtering, the ZnO films fabricated by ion beam sputtering deposition have disordered growth orientation, bigger surface roughness and higher electrical resistivity.

We report on the photocurrent generated by nanometer grains embedded in hydrogenated amorphous silicon (a-Si:H), i.e., the hydrogenated nanocrystalline silicon (nc-Si:H) thin film. The embedded nanometer grains within the a-Si:H boundaries are found to be a narrow continuous energy band in the a-Si:H band-gap, from which the transitions can effectively generate the free electron-hole pairs, resulting in the observed high photocurrent. The high density of nanometer Si crystals is a good means to improve the photo current response, and the fabrication of the low-cost infrared photo detector by a single layer of nc-Si:H thin film on glass substrates is also expected.

We intentionally patterned Si-rich SiN_x nanoislands on sapphire substrates and found the SiN_x significantly influenced the subsequent growth of GaN films. Distinct GaN islands of triangular base were formed caused by the enhanced diffusion and regrowth anisotropy during the annealing processes of GaN nucleation layers. Subsequent growth of GaN epilayers at high temperature with initial low V/III ratios on the nucleated triangular islands resulted in island coarsening and shape variations from triangular to hexagonal due to the dominating gas phase transport growth mechanism and limited diffusion length. Further growth with high V/III ratios eventually resulted in layer-growth with surface roughness of ~2.6 Å. Both AFM and XRD results showed a significant improvement of the crystalline qualities with estimated threading dislocation (TD) density of about 1×10⁸ cm^-2 when Si-rich SiN_x nanoislands patterning was performed. Photoluminescence measurements showed that the yellow and blue emissions were substantially suppressed.

Well-defined lamellar-structured ZnO-SDS hybrid thin films were grown on ITO glass from zinc nitrate solution containing anionic surfactant sodium dodecyle sulfanate (SDS) via the potentiostatic electrodeposition route. The effect of deposition potentials on the self-assembly process at the interface was discussed. Results show that the period of the lamellar structure doesn't have obious dependance on the deposition potential. However, the quality of lamellar structures incorporated in the ZnO films can be enhanced as the deposition potential increases. Optical analysis showed that the hybrid films had good optical qualities, and their optical transmittance decreased as the deposition potential increased.

The highly (001)-orientated α-HgI₂ film was deposited by hot wall physical vapor deposition (HWPVD) technology. The scanning electron microscopy (SEM), X-ray diffraction (XRD), dark current versus applied voltage and capacitance-frequency characteristics analysis showed that the film was compactly formed by separated columnar monocrystallines with uniform orientation along c-direction and with high resistivity (2.5×10¹²Ω•cm) and low dark current.

Highly oriented polycrystalline α-HgI₂ thick films are fabricated by physical vapor deposition method under the conditions of 59KHz ultrasonic wave and relatively lower source temperature of 80°C. The ultrasonic wave is used in the process of physical vapor deposition films preparation for the first time. With the effect of ultrasonic wave, the film quality and the growth rate can be obviously improved. The growth mechanism as well as impacts of ultrasonic wave is also discussed.

Fabrication of deep pores and trenches in nano-size will enable the embedded nanodevice integrated with silicon IC. However, the conventional dry etching method needs very expensive equipment and the process is quite complicated. Recently, electrochemical etching was developed to fabricate structures with high aspect ratio. Anodization was performed in a solution of HF with certain concentration mixed with ethanol by 1:1 in volume. The backside of the wafer was illuminated by a halogen lamp. The whole etching system was monitored by a computer system. It is found, in case of etching in a low current with 5%HF electrolyte, the size etched pores can be less than 100 nm. However, the deep trench structures becomes a line array of pores. Further work is in progress to investigate the detail.

The main element of thin film solar cell is silicon. Because of the special mechanical characteristic of silicon, the method of loading pressure on the thin film solar cell and the value of pressure is the key problem which must be solved during the manufacturing of thin film solar cell. This paper describes the special mechanical characteristic of silicon, discussed the test method overall; value of pressure on thin film solar cell; the elements and the method of load by ANSYS finite element, according to these theory analysis, we obtained the key conclusion in the actual operation, these result have a great meaning in industry.

This paper reviews our research on photon upconversion devices for wavelengths from 1.5 μm to 0.87 μm. The 1.5 μm is chosen for its importance for eye-safe active imaging; whereas 0.87 μm corresponds to the bandgap of GaAs which is the active region of our high efficiency light emitting diode (LED). The basic idea is to integrate a 1.5 μm detector with a 0.87 µm LED, connected in series. The detected photocurrent drives the LED, thereby achieving the upconversion. Various approaches of integration methods and device designs have been tested. The upconversion approach provides an alternative to the standard hybrid integration with readout circuits and may be advantageous for some applications.

Tunneling quantum dot photodetector (T-QDIP) structures designed for multi-band infrared and heterojunction detectors for ultraviolet (UV) to infrared (IR) radiation detection are presented. In T-QDIPs, photoabsorption takes place in InGaAs QDs due to intersubband transitions of carriers. Photoexcited carriers are selectively collected through resonant tunneling, while the dark current is blocked by AlGaAs/InGaAs tunneling barriers. This approach to block dark current without reducing photocurrent was observed in a detector responding at ~ 6 and ~ 17 μm up to 300 K. In addition, UV/IR dual-band detectors were developed based on GaN/AlGaN Heterojunction Interfacial Workfunction Internal Photoemission (HEIWIP) structures. A typical HEIWIP detector structure consists of a single (or series of) doped emitter(s) followed by an undoped barrier(s) between two highly doped contact layers. Reported UV/IR structures use n-doped GaN emitters and Al_xGa_1-xN barriers. The UV response is due to interband (valence-to-conduction) transitions in the undoped AlGaN barrier, while the IR response arises from intraband transitions in the n-doped GaN emitter. Preliminary detectors were successfully demonstrated with a 360 nm threshold UV response up to 300 K and 8-14 μm IR response up to 80 K.

Multilayer mirrors are the important optical elements for astronomical observation at extreme ultraviolet region. In this article, three kinds of multilayer mirrors were introduced for solar observation and magnetosphere observation. Mo/Si multilayer mirror was fabricated for solar Fe-XII emission line at wavelength of 19.5nm. For solar He-II radiation at 30.4 nm, Mo/Si, Si/SiC, Si/C, Si/B4C and Mg/SiC multilayers were investigated, and the measurements results shows that Mg/SiC multilayer provides the highest reflectivity of 43.8% at incidence angle of 5 degree. The third multilayer mirror was a dual-function mirror used for earth's magnetosphere observation, which requires high-reflective for He-II emission line at wavelength of 30.4nm but anti-reflectance at 58.4nm from ionosphere He-I emission. Using aperiodic Mg/SiC multilayer, the dual-function multilayer mirror was designed. Compared to periodic multilayer, the dual-function multilayer suppresses the reflectivity for He-I at 58.4nm from 2.2% to 0.1%, without loss of the reflection for He-II at 30.4nm, significantly.

Synthesis of boron nitride (BN) and boron carbon nitride (BCN) films is carried out by plasma-assisted chemical vapor deposition. The electron affinity of the BN and BCN films is estimated from the threshold energy of the photoelectron yield and the bandgap energy. The negative electron affinity appears on the BN surface, while the positive electron affinity increases on the BCN surface with increasing C composition ratio. It is found that a reduction in the electron affinity occurs due to N₂ plasma treatment rather than H₂ plasma treatment for the BCN film. Field emission characteristics of the BN and BCN nanofilms are investigated. The turn-on electric field of the electron emission does not increase in the region of the C composition ratio lower than 20 %. This is due to the effects of increasing electron affinity and decreasing conduction band discontinuity between the BCN nanofilm and Si substrate. It is demonstrated that field emission characteristics of the graphite nanofiber are improved significantly by coating with BN nanofilm.

Crack-free AlGaN-GaN HEMT materials with 1.2-μm-thick were grown on high-resistivity Si(111) substrates by MOCVD. The sample showed a high 2DEG mobility, 1350cm²/V•s at 300K and 5900cm²/V•s at 77K, respectively. High optical and structural qualities were confirmed by PL and XRD. The dc and rf characteristics of AlGaN-GaN microwave power devices with 0.4μm gate length and 1mm of the gate width were probed. The saturated drain current density was around 0.8A/mm, and the peak transconductance was beyond 230mS/mm. Tunning for a maximum output power of 5.1W, a gain of 9.1dB and a peak power-added efficiency (PAE) of 35% was obtained, respectively.

Single point defect microcavity possesses only the degenerate dipole modes under certain photonic crystal structure parameters. By deforming lattice structure, the degeneracy of the dipole modes has been broken. Theoretical simulation shows the large splitting of 65nm between the splitted x-mode and y-mode, approximate to the luminescent gain spectrum, which benefits for the single mode lasing. Experimentally the single dipole mode lasing, y-mode, is achieved in the deformed microcavity.

In this work, the guided modes of a photonic crystal polarization beam splitter (PC-PBS) are studied. We demonstrate that the transmission of a low-loss photonic crystal 120° waveguide bend integrated with the PBS will be influenced if the PBS is multi-moded. We propose a single-moded PC-PBS structure by introducing deformed structures, and it shows twice the enhancement of the transmission. This device with remarkable improvement of performance is promising in the use of photonic crystal integrated circuits design.

Whispering gallery modes (WGMs) in microcavities possess ultra- high cavity Q factor. Such microcavity are easy to be fabricated, so WGMs have attracted much attention in the area of photonics and integrated photonic circuits. It is well known that the effect of total internal reflection restricts the size of this mirocavity. Such drawback goes against the integration of photon. However, the photonic crystal microcavities (PCMC) make a breakthrough recently. The WGMs in the PCMC are possible to gain both ultra-high Q and ultra-small mode volume. In this paper, the property of the mode in photonic crystal ring cavity is analyzed by FDTD and PWE. By modifying the airholes in the corners of the ring cavity, we can obtain the WGM. Also the Q factor of WGM in photonic crystal ring cavity is calculated. This favors the design of the photonic crystal microcavity components.

The La_0.7Ca_0.3MnO₃ (LCMO) films were prepared by the pulse laser deposition method on Pt/Ti/SiO₂ /Si substrates under the O₂ partial pressures of 0.01Pa, 1Pa, and 10 Pa, respectively. XRD patterns show that LCMO film grown under the O₂ partial pressure of 0.01Pa exhibited good crystallinity and (110) preferred orientation. Due to the strong collision in the plume, the crystal quality of LCMO films grown under 1Pa and 10Pa decreased remarkably. Electrical measurements show that the LCMO films grown under low O₂ partial pressure has stable resistance switching property. The oxygen content but crystallinity is a key factor for the resistance switching property of LCMO film. The lack of oxygen promotes the resistance switching properties of LCMO films.

In this paper, WO₃ sol was prepared via the sol-gel method, and palladium chloride powder was dissolved in the sol in different W: Pd molar ratios. Pd doped WO₃ films were coated on silicon wafers and ordinary slide glasses by dip-coating method. The grain distribution of WO₃ sol doped with PdCl₂ was measured by Laser Particle Size Analyzer. Surface morphology and microstructure of WO₃ films which doped or undoped with PdCl₂ were analyzed by AFM, which show that PdCl₂ has an important effect on the structure of the WO₃ films. The gasochromic properties of the films are investigated by UV-Vis spectrophotometer. The WO₃ films show good gasochromic properties. The effect of concentration of PdCl₂ on gasochromic kinetic process of WO₃ films was investigated. Finally the modulation of the light transmittance by the gasochromic films was discussed.

Beam coupling theory for the nonlocal Raman-Nath gratings was developed, which showed that the gain initially increased exponentially with the sample thickness, then deviated from the exponential relation and lowered gradually. It was predicted that large thickness and high intensity sensitivity were simultaneously necessary for the sample to obtain larger gain. The quantitative relation between the signal gain and the sample thickness was investigated experimentally by using a multilayer photorefractive liquid crystal structure to increase the overall interaction length, and the experimental result fitted the theory nicely.

In this paper we constructed nematic liquid crystal (NLC) cells with the gold film as one substrate as well as the cells with the gold film covered with decanethiol and hexadecanethiol self-assembled monolayers (SAMs). We found the photocurrents in these three kinds of cells all increased linearly with the power of the 632.8nm illuminating beam. And the existence of alkanethiol SAM or application a high voltage could enhance the growth rate of the above linear relations. These indicated that the current originated from the light induced carrier injection from the gold electrode to NLC film, and a model of photocurrent limited by near-electrode excitons was introduced to explain the photoinduced carrier injection.

In order to improve the opto-electronic conversion efficiency of solar cells, antireflection coatings (ARCs) have been drew a great attention for the application in the terrene. Generally, the coating is obtained by vacuum processing such as thermal evaporation, reactive sputtering and plasma-enhanced chemical vapor deposition (PECVD). In this work, multi-layer antireflection coatings have been performed by a modified sol-gel technique, which is low-cost and simple. The multi-layer films consisted of SiO₂ and TiO₂. The physical phase and morphology of each layer were characterized by atomic force microscopy (AFM). The TiO₂ single-layer and SiO₂/TiO₂ double-layer antireflection coatings were respectively annealed at 150°C, 350°C and 550°C. The sols of TiO₂ and SiO₂ were aged for 24 hours and then were spin coated on the Si substrate. It was found that the reflectance of double-layer ARCs was generally lower than that of single-layer ones. The reflectance of films without being aged was lower than that of sols were aged for 24 hours. In all samples, the SiO₂/TiO₂ double-layer film which was annealed at 150°C and which sols were not aged for 24 hours had the lowest reflectance.

In this paper, successful fabrication of DLC thin films with tunable band gaps deposited by r.f. plasma-enhanced chemical vapor deposition (RF-PECVD) under different bias voltages is reported. By Ultraviolet Transmission Spectroscopy, it is revealed that the band gaps vary from 1.0eV to 2.1eV, which can cover the most important part of the solar spectrum for terrestrial application solar cells. And the mechanism that band gaps of DLC films varied with the bias voltages was analyzed by X-ray Photoelectron Spectroscopy (XPS). It is gotten that the different ratio of sp²/sp³ results in different band gaps, which is apparently resulted by different bias voltage during the deposition process. The band gap tends to have higher value at less sp² content. The experiment results show that DLC multi-layer films can be used as an effective absorber layer for thin films solar cells.

The polysilicon ohmic contacts to n-type 4H-SiC have been fabricated. TLM (Transfer Length Method) test patterns with polysilicon structure are formed on N-wells created by phosphorus ion (P⁺) implantation into Si-faced p-type 4H-SiC epilayer. The polysilicon is deposited using low-pressure chemical vapor deposition (LPCVD) and doped by phosphorous ions implantation followed by diffusion to obtain a sheet resistance of 22Ω/square The specific contact resistance ρ_c of n⁺ polysilicon contact to n-type 4H-SiC as low as 3.82×10^-5Ωcm² is achieved. The result for sheet resistance R_sh of the P⁺ implanted layers in SiC is about 4.9kΩ/square. The mechanisms for n⁺ polysilicon ohmic contact to ntype SiC are discussed.

In this paper, we present some results on FeCoB-based microwave band-stop filters. These structures, prepared on GaAs substrates, are compatible in size and growth process with on-chip high-frequency electronics. The band-stop filters have been realized with microstrips which incorporate ferromagnetic and dielectric layers to absorb microwave energy at the ferromagnetic resonance (FMR) frequency. The absorption notch in transmission can be tuned to various frequencies by varying an external applied magnitic field. For our devices, which incorporate FeCoB as the ferromagnetic material, the resultant FMR frequencies range from 12-22 GHz for applied fields up to only 1000 Oe. Comparatively, the frequency range of those devices using permalloy and Fe is substantially lower than FeCoB-based devices for applied the same fields. We constructed devices using monocrystalline FeCoB films grown in a sputtering system. Our devices are of different construction than other dielectric microstrips and show much improvement in terms of notch width and depth. The maximum attenuations of 3.5 dB/cm and 90dB/cm are observed respectively in two different structures.

Surface transverse waves (STW) resonators exhibit substantial advantages over conventional surface acoustic wave (SAW) resonators without further demands for new materials or improved design and technology. They demonstrate higher operating frequencies, better temperature stability, higher intrinsic material quality and etc. In this work, the low loss and high quality factor STW with center frequency at 421 MHz fabricated with a line width of 3 μm were uniquely designed and fabricated on AT quartz substrate. The insertion loss of the device was as low as 2 dB, and the loaded quality factor was as high as 1000. Insertion losses as function of structure parameters are discussed.

This paper discusses some advantages of IC thin film technology in realizing RC array that traditional thick film technology does not have, which make IC thin film technology the mainstream in realizing RC array devices. Then it focuses on how to use IC thin film technology to realize high precision RC array, some practical techniques are put forward, based on our experiments and experience in layout design and fabrication. These techniques are demonstrated separately according to the respective characteristics of resistor and capacitor. Finally, the different ranges of precision of the devices tested in different ways through specific experiments are given.

Mesoporous TiO₂ particles were prepared and characterized by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM), which confirmed that well-organized mesostructure has been formed. Near-infrared absorbing tetra-amino manganese (II) phthalocyanine (TAMnPc) was synthesized and employed as sensitizer and TAMnPc sensitized mesoporous TiO₂ (TAMnPc-TiO₂) films were prepared and characterized by electronic absorption spectrum. Compared with bare TiO₂ films, TAMnPc-TiO₂ films exhibit an additional Q absorption band in near-infrared region. Current-voltage (I-V) characteristics of TAMnPc-TiO₂ films in dark and under irradiation were tested. Adsorption of TAMnPc onto mesoporous TiO₂ leads to a significant rise in photoconductivity.

A heterostructure of nanocrystalline diamond film / n-Si was fabricated successfully, where the un-doped p-type nanocrystalline diamond (NCD) film was grown by an electron assisted hot filament chemical vapor deposition (EA-HFCVD) technology. The structure and morphology of the NCD film were analyzed by Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). I-V characteristic of the p-NCD/n-Si heterojunction indicated that this structure was rectifying in nature with a turn-on voltage of ~0.5V. The p-NCD/n-Si heterostructure was also used for UV detector applications. Operating at a bias voltage of 10V, this photodetector showed a significant discrimination between UV and visible light, and the UV/visible-blind ratio was about three orders of magnitude.

Potentially low cost and large area polycrystalline mercuric Iodide (HgI₂) is one of the preferred materials for the fabrication of room temperature X-ray and gamma-ray detectors. In this paper, the technique of fabricating polycrystalline HgI₂ detectors was studied and the energy resolution of 13.1% for 5.5 MeV ²⁴¹Am α particles at room temperature was obtained for the first time. The optimal choice of particle injecting from negative interface enhances the collection efficiency.

In this report, p-type macroporous silicon has been prepared by anodization. A phosphorus diffusion step is employed for the formation of three dimensional pn junction structures on this macroporous silicon. I-V and C-V measurement were employed to characterize the electrical properties. The results were compared with numeric simulation with T-SUPREM4 and MEDICI. It has been demonstrated that three-dimensional structure can increase the effective junction area and the collective efficiency remarkably, and hence improve the performance of semiconductor radiation detector.

The microelectromechanical variable optical attenuator (VOA) using an electrostatic beam combined with a fiber-optic collimator has designed and fabricated. This VOA is based on silicon-on-insulator (SOI). When the driving voltage is applied to the beam and the substrate, the beam will yield a vertical displacement. Then the reflected light can't enter into the coupled fiber completely. Based on electrostatic actuation, the attenuation level is adjusted by changing the displacement of the beam. The relationship between the voltage and the displacement was analyzed by using ANSYS, a finite element analysis software package. The result of the simulation shows that the attenuator with the new structure has good performances. The fabrication steps use two wet etching processes. The active layer of SOI wafer is first patterned into the mirror sharp by TMAH, and the backside is etched to the buried oxide (BOX) using a 2-μm-thick SiO₂ mask. After releasing the structure in hydrofluoric acid, gold layers are deposited by vacuum evaporation. The testing is still in progress.

A quartz crystal microbalance (QCM) gas sensor with polysiloxane sensing film was fabricated for detection of dimethyl methyl phosphonate (DMMP), the simulant of chemical warfare agents (CWAs). Poly(methyl-3,3,3-trifluoropropylsiloxane) (PMTFPS) was oxygen plasma treated and then grafted with sulfosalicylic acid (SSA). The resultant SSA modified PMTFPS (SMP) was drop-coated on the electrode of QCM. Compared with the PMTFPS-QCM and SSA-QCM sensors, the sensitivity of SMP-QCM sensor was much higher. However, the SMP films showed less resistance to humidity variations. The selectivity of SMP-QCM sensor to DMMP was also investigated, and better results was showed out after SSA grafted.

Polyaniline/titanium dioxide (PANI/TiO₂) nanocomposite thin films were synthesized by in-situ self-assembly method, which were doped with p-toluene sulphonic acid (p-TSA) and hydrochloric acid (HCl), respectively. The thin films were characterized by using UV-Vis absorption spectroscopy and scanning electron microscope (SEM), and the NH₃ gas sensitive properties of the thin films were investigated at room temperature. The results showed that the PANI/TiO₂ thin film doped with HCl was superior to that doped with p-TSA in terms of response-recovery characteristics. The surface morphology characterization of the thin films were performed to explain the different gas-sensing properties.