Two dimeric trimeric phenylenvinylene derivative 2, 5, 2', 5'-tetrakis (4'-fluorostyryl) biphenyl (P-F-TSB) and 2, 5, 2', 5'-tetra (p-trifluoromethylstyryl)-biphenyl (TFM-TSB) have been synthesized as new electroluminescent (EL) materials. P-F-TSB exhibits good color purity, high luminance of blue light-emission in organic light-emitting devices. Maximum brightness and luminous efficiency are of 1828 cd/m2 and of 1.92 cd/A, respectively. CIE coordinates are x=0.20 and y=0.22. Interestingly, we can fabricate single layer white light-emitting device using TFM-TSB as emitting layer. The broad electroluminescence emission band may attribute to long-wavelength excimer and electromer emission in addition to the blue component from singlet excited state of individual TFM-TSB molecule. Furthermore, white-light emission can also be obtained with a typical three-layer structure of ITO/ NPB (50 nm)/ TFM-TSB (50 nm)/ Alq3 (30 nm)/LiF/Al device. The maximum brightness of this device is 809 cd/m2 at 217 mA/cm2 and 13V, and the maximum luminous efficiency is 1.49 cd/A at 11 mA/ cm2 and 8V.
We studied electron injection form Al cathode into the tris(8-hydroxyquinoline)aluminum (Alq3). When a thin CsCl layer is inserted between Alq3 and Al, a substantial enhancement in electron injection is observed. The results show that the device with the cathode containing the ultrathin CsCl layer has a higher brightness and electroluminescent efficiency than the device without this layer. Further, organic light-emitting devices (OLEDs) based on tris-(8-hydroxyquinoline)aluminum using a trilayer of CsCl/LiF/Al as cathodes have been fabricated. The results show that the device with the cathode containing 0.5 nm CsCl layer and 1.0 nm LiF layer has a higher brightness and electroluminescent efficiency than that of the device with LiF/Al or CsCl/Al cathodes. The maximum EL efficiency of the CsCl/LiF/Al cathode device is 3.41 cd/A, which is higher than the 2.74 cd/A of the LiF/Al device and 2.49 cd/A of the CsCl/Al device.
In this paper, a modified four-transistor pixel circuit for active-matrix organic light-emitting displays (AMOLED) was developed to improve the performance of OLED device. This modified pixel circuit can provide an AC driving mode to make the OLED working in a reversed-biased voltage during the certain cycle. The optimized values of the reversed-biased voltage and the characteristics of the pixel circuit were investigated using AIM-SPICE. The simulated results reveal that this circuit can provide a suitable output current and voltage characteristic, and little change was made in luminance current.
Blue and white organic light-emitting devices using a novel dimeric trimeric phenylenvinylene (TPV) derivative , 2,5,2',5'-tetrakis(4'-biphenylenevinyl)-biphenyl (TBVB) containing a biphenyl center are fabricated. Structures of these devices are simple, where tris (8-hydroxyquinoline) aluminum (Alq) and N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) are used as electron-transporting and hole-transporting layers, respectively. In blue device, TBVB is used as light-emitting layer. The peak of electroluminescent (EL) spectra of the device with TBVB is at 468 nm, and its maximum efficiency is greatly higher than that of the reported oligomer poly(phenylenvinylene) (PPV) devices. By inserting an ultra thin layer of rubrene between TBVB and Alq layers, a fairy pure white OLED with CIE coordinates of (0.33, 0.34) is realized. Its maximum luminances and efficiencies are 4025 cd/m2 and 3.2 cd/A, respectively.
Efficient white organic light-emitting devices are demonstrated by inserting a thin layer of tris (8-hydroxyquinoline) aluminum (Alq) doped with 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) (DCJTB) into N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) layer. Alq without doping is used as an electron-transporting layer and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine or BCP) as an exciton-blocking layer. NPB layers are separated by the doped Alq layer, the layer that sandwiched between BCP and doped Alq layers acts as a blue-emitting layer, and the other as a hole-transporting layer. The doped Alq layer acts as a red and green-emitting as well as chromaticity-tuning layer, whose thickness and position as well as the concentration of DCJTB in Alq permit the tuning of the device spectrum to achieve a balanced white emission with Commission Internationale De L'Eclairage coordinates of (0.33, 0.33), which are largely insensitive to the applied voltages, especially at high brightness (>1000cd/m2). The device have maximum luminance and efficiency of 6745 cd/m2 and 2.56 cd/A, respectively.
The diffraction characteristics are analyzed for a polymer arrayed-waveguide grating (AWG) multiplexer around the central wavelength of 1.55 μm with the wavelength spacing of 1.6 nm. The diffraction loss and diffraction efficiency in the input and the output slab waveguide are investigated and discussed for different values of parameters, such as the core width, pitch of adjacent waveguides, the number of arrayed waveguides, taper end width of waveguides, and number of output wavelength. Finally, we give a set of parameters which have been optimized in this device.
In this paper, a 9 X 9 Polymer/Si AWG was designed and fabricated. The cladding material is poly-methyl-methacrylate-co-glyciclyl methacrylate (PMMA-GMA) and the core material is the mixture of
PMMA-GMA and bis-phonel-A epoxy. During the fabrication process of the Polymer/Si AWG device, We used aluminum as mask on polymer instead of conventional photoresist as mask. The results show that the device is good for the wavelength division multiplexing (WDM) system. The output characteristics of the device were measured by a system based on the tapered fiber. The results show that our polymer/Si AWG meets the designed device well.
In this paper, the basic principle, details of fabricating process and measuring results were described for a polymer/Si arrayed waveguide grating (AWG) multiplexer around the central wavelength of 1.550 micron with the wavelength spacing of 1.6nm. The fluorinated polymer was used to fabricate AWG to reduce the optical loss, but the fluorinated material was expensive, so we initially adopted the polymer of polymethylmethacrylate(PMMA) type to go on technologic research. The regulated curve of refractive index was given for the core polymer. In order to obtain better shape of the waveguide after the reactive ion etching (RIE) using oxygen, an aluminum film as mask was used on polymer instead of conventional photoresist as mask. In order to reduce radiation loss of underciadding layer to Si
substrate, the underciadding layer thickness was increased to 11 micron through two times of spin-coating, thus the radiation loss was reduced to the order of 0.001dB. The measuring results indicates fabricated optical waveguide achieved single-mode transmission.
Based on the arrayed waveguide grating (AWG) multiplexer theory, some important parameters are optimized for the structural design of a polymer AWG multiplexer around the central wavelength of 1.55μm with the wavelength spacing of 1.6 nm. These parameters include diffraction order, focal length of slab waveguides, number of arrayed waveguides are determined. Then, a schematic waveguide layout of this device is presented, which contains 9 input and 9 output channels. The transmission and loss characteristics are analyzed. The computed results show that when we select the core thickness as 4 micron, width as 6 micron, pitch of adjacent waveguides as 26 micron, diffraction order number as 78, distance between the focal point and the origin as 8340 micron, the total loss of the device can be dropped to about 5.7dB, and the crosstalk among output channels can be dropped below -50dB.
An arrayed-waveguide grating multiplexer is demonstrated, which is successfully designed and fabricated . A wavelength channel spacing was 1 .6nm, a crosstalk of less than —20dB and the insertion loss was 7-12dB around 1.55?m. The polarization-dependent wavelength shift was very small without special compensation methods.
We demonstrate an efficient organic electroluminescent devices with p-i-n structure. Anamorphous starburst, 4,4',4'-tris(3-methylphenylphenylamino)triphenylamine doped with a strong organic acceptor, tetrafluoro-tetracyano- quinodimethane serves as the p-type hole transport layer, and 4,7-diphenyl-1, 10-phenanthroline doped with Li as the n-type electron transport layer. A breakthrough is achieved in the performances of device based on pure 8-tris- hydroxyquinoline as an emitter: 100cd/m2 at 2.52V, 1,000cd/m2 at 2.9V and the maximum luminance and efficiency reach 66,000cd/m2 and 5.25 cd/A, respectively. The efficiency can be kept above 3cd/A in a very large luminance region from 100 to 55,000cd/m2.
The single layer of organic optical microcavity with 1D distributed Bragg reflectors (DBRs) was fabricated. The PL emission properties of the microcavity were explored at the two sides, which show different characteristics due to the asymmetric structure. The PL emission peak of Alq film is at 5113 nm with a half width of 78nm. Compared with the Alq film, the emission of microcavity from the top DBR side shows a narrow peak at 494nm with a half width of 4.6nm and an enhanced factor of 11, and 606nm with a half width of 6.6nm.
A graded doping technique was presented to fabricate high brightness and high efficiency OLEDs, in which a copper phthalocyanine(CuPc) film acts as buffer layer (alpha) -naphthylphenybiphenyl amine(NPB) film as hole-transport layer and a tris(8-hydroxyquinolinolate)aluminum(Alq3) film as the electron-transport layer.The luminescent layer consists of the mixture of NPB,Alq3 and an emitting dopant 5,6,11,12-petraphenylnaphthacene(Rubrene), where the concentration of NPB raised while the concentration of Alq3 was declined gradually in the deposition process. The graded doping device exhibited the maximum emission of 50000cd/m2 at 35v and the maximum efficiency of about 8cd/A at 9v, respectively, which have been improved by four times in comparison with the conventional doped devices.
A bilayer is used as an electrode for organic light-emitting devices. The bilayer consists of a Sn layer adjacent to Alq layer and an Al outerlayer. The effects of a controlled Sn buffer layer on the behavior of ITO/CuPc/NPB/Alq/Sn/Al light-emitting devices are described. It is found that both electron injection efficiency and electroluminescence are significantly enhanced when the thickness of Sn layer is suitable. The enhancement is believed to be due to increased electron density of Sn layer near the Sn/Al interface .
Organic Metal microcavities were fabricated by using full- reflectivity metal film and semi-transparent metal film as cavity mirrors. Compared with the conventional organic microcavity, the typical structure of which is Glass/DBR/organic layers/metal mirror, a short cavity-length microcavity can be obtained by using metal mirrors. Red, green and blue emission of the microcavities were realized under photoexcitation due to the change of the thickness of the Alq3 layer. The measured microcavity emission spectra were shown to be roughly in agreement with the theoretical calculation spectra using the characteristic matrix method. The results implied that organic metal microcavity has some advantages in realizing the pure single mode RGB emission.
An organic quantum-well structure electroluminescent device is fabricated by a doping method. The quantum-well structure consists of (formula available in paper) as potential well and emitter, undoped NPB as a barrier potential. Compared with a conventional doping structure device, both the maximum brightness and electroluminescent (EL) efficiency of the device are enhanced, reaching 40 000 cd/m2 and 5.6 cd/A, respectively. Especially, with the increase of the drive voltage, the EL efficiency (cd/A), after reaching its maximum, declines very slowly, almost independent of the drive voltage in a wide range from 5V to 13V. The characteristic may be useful in improving the lifetime of the device.
On the basis of the arrayed waveguide grating (AWG) multiplexer theory, some important parameters are optimized for the structural design of a polymer AWG multiplexer around the central wavelength of 1.55micrometers with the wavelength spacing of 1.6nm. These parameters include the thickness and width of the guide core, mode effective refraction indicees and group refractive index. Pitch of adjacent waveguides, diffraction order, path length difference of adjacent arrayed waveguides, focal length of slab waveguides, free spectral range, number of input/output waveguides, and that of arrayed waveguides.
Under the condition of zero net strain, the effect of high temperature on the optical gain and threshold characteristics and the dependence of the characteristic temperature on the cavity length are analyzed theoretically for InGaAs/InGaAsP strain-compensated multiple quantum well (SCMQW) lasers lattice-matched to InP around 1.55 micrometers wavelength emission. The computed results show that as the temperature increases, both the threshold carrier density and the threshold current density increase. As the cavity length increases, the characteristic temperature increases and the temperature dependence becomes better. The characteristic temperature of a SCMQW laser is higher than that of a strain-compensated single quantum well (SCSQW) laser. Therefore, the temperature dependence of the SCMQW laser is better than that of the SCSQW laser. In addition, we find that in order to always keep 1.55 micrometers wavelength emission, certain relations exist among the well width, cavity length and temperature.
We designed some important parameters and analyzed loss characteristics of a 8X8 polymer arrayed waveguide granting multuplexer that operates around the wavelength of 1.55 micrometers and the wavelength spacing was 16nm. The total loss of the device includes the diffraction loss in the input and output (I/O) slab waveguides, bent loss caused by the AWG and 1/O channels, and leakage loss resulted from the high refractive index substrate. The effects of some structural parameters on the loss characteristics are investigated and discussed. The computed results show that when we select the core thickness as 4 micrometers , core width as 6 micrometers , pitch of adjacent waveguides as 15.5 micrometers , diffraction order number as 50, the number of the arrayed waveguides as 91, that the I/O channels as 8,confined layer thickness between the core and the substrate as 6 micrometers , distance between the focal point and the origin as 5500 micrometers , and central angle between the central waveguide and the vertical of the symmetrical line of the device as 60 deg, then the total loss of the device can be dropped to about 3.73 dB.
A new organic material Ligand Lhn4 is used to fabricate organic light emitting diodes. There are two peaks in the Photoluminescence (PL) spectrum of Ligand Lhn4; they are 444 nm and 482 nm. Organic light emitting diode with Al/LiF(0.5 nm)/Ligand Lhn4(50nm)/NPB(50nm)/ITO structure was grown by evaporation. The electroluminescence (EL) spectrum shows there is one peak wavelength for OLED located at 486 nm. The full width of half maximum (FWHM) is about 112 nm, it mean the material Ligand Lhn4 is quite fair for fabrication of white light OLED. The OLED start emit a white near to blue color light at 2 V voltage, and the color have no change as the voltage increasing. The I-V and Brightness vs. Voltage curves were measured at air. The maximum brightness is 300cd/m2 at voltage of 15 V. A doped device Al/LiF/BePP2:Ligand Lhn4(10%)/NPB/ITO is fabricated to improve the brightness and efficiency of OLED based on Ligand Lhn4.
A novel blue organic light emitting diode is fabricated based on a new organic material. Dipyrrole3, which can emit a pure blue light. The Dipyrrole3 is used as a dopant and is doped into an electron-transporting hose. NPB is used as the hole transport layer. The device consists structure or ITO/NPB/Begg2:Dipyrrole3 (100:5)/BePP2/LiF/Al. It shows a bright blue light emission layer at 451nm and 480nm, the full width at half maximum is 61nm. The maximum luminescence is 2600cd/m2 at a voltage of 20V. The peak power efficiency is 0.7651m/W at a voltage of 7V.
An improved fabrication process and related experiment results of an InP-based monolithic integrated transmitter OEIC with a 1.55 micrometers MQW laser diode (LD) and an InP/InGaAs heterojunction bipolar transistors (HBT) driver circuit are presented. The epitaxial structure of the laser and driver circuits were continuously grown on semi- insulating Fe-doped InP substrate by a metal-organic chemical vapor deposition system using a vertically integration. HCL, H3PO4/H2O2 and HBr/HNO3 solution system were involved as selective or nonelective wet chemical etching respectively for the epitaxies of InP, InGaAs and InGaPAs. Both a nearly-standard contact photolithography depending on a two-step exposure technique and an electrical connection related to smoothly wet chemical etching profile of InP and InGaP in the crystal direction of (01-1) were developed in the process. The laser diode with a 3-um-wide ridge waveguide forming by a double- groove process self-aligned to the metal contact of P-type region showed an average threshold current as low as about 10mA. The HBT with a 120-nm-thick base layer performed a DC current gain of about 60-70 and an emitter-collector breakdown voltage of up to 4-5V. A clear eye diagram of the monolithic transmitter under a pulsed operation with 622Mbit/s bitrate nonreturn-to-zero pseudorandom code was obtained.
A white light-emitting organic/polymeric electroluminescent (EL) device with multilayer thin-film structure is demonstrated. The device structure of glass substrate/indium-tin oxide/poly(N- vinylcarbazole)/phenylpyridine beryllium(BePP2)/8- (quinolinolate)-aluminum (Alq) doped with 5,6,11,12- petraphenylnaphthacene/Alq/LiF/Al was employed. The turn-on voltage is as low as 2.9 V. Blue fluorescent BePP2 yellow fluorescent rubrene, and green fluorescent Alq are used as three primary colors. The Commission Internationale de l'Eclariage coordinates of the emitted light are at 10V, which is located in the white-light region. Bright white light, over 6800cd/m2, was successfully obtained at about 17V, and the maximum efficiency reaches to 1.38m/W at 8.5V.
Dye TPB has been successfully introduced into polymeric multilayer films by means of LB technique without any chemical modification. X-ray diffraction and optical absorption data indicate that the films have ordered structure with a period of about 5.8 nm that is similar to a superlattice. The TPB doped polymeric LB films have also been used to fabricate an electroluminenscence (EL) device that emits in the blue region at room temperature. Compared with cast films, the photoluminescence and electroluminescence spectra of the TPB-doped LB films show that the exciton shifts to higher energy and that the full width at half maximum of the emission peak becomes narrower.
KEYWORDS: Laser stabilization, Information operations, Optoelectronics, Transmission electron microscopy, Process modeling, Differential equations, Cladding
In this paper, the stability of strained MQWs in laser structure is discussed. The excess stress is the driving force of misfit dislocation multiplication and is a very important factor of strained MQWs stability. So we calculate the excess stress using the single-kink model. Our results show that the maximum position of excess stress is related to the barrier and well thicknesses and mismatches in the well(s). The lattice-matched barriers can dilute the excess stress. The capping layer can also dilute the excess stress in a certain degree. We then calculate the strain relaxation using the dynamic model of dislocations. In this model, the strain relaxation is driven by the excess strains. In this paper, the criteria of the stability of MQWs in laser structure is that the density of dislocations (or the strain relaxation) is less than a certain value. In this way, the barriers and capping layer are both important factors of MQWs stability. The method can be used to better the MQWs in laser structure.
In terms of the parameter interpolation principle, calculations are performed for bandgaps and band offsets in strain-compensated InzGa1-zAs/InxGa1-xAsyP1-y multiple quantum well structures on InP. Relations between strains and material compositions in InzGa1-zAs wells and InxGa1-xAsyP1-y barriers are analyzed, and relative ranges of strains are evaluated. Bandgaps of InzGa1-zAs wells and InxGa1-xAsyP1-y barriers for heavy- and light-holes are studied, and relative ranges of bandgaps are estimated. Dependence of band offsets of conduction band and valence band for heavy- and light-holes on strain compensation between InzGa1-zAs wells and InxGa1-xAsyP1-y barriers is investigated, and variation of band offsets versus strain compensation is discussed. The computed results show that strains, bandgaps and band offsets are functions of material compositions, strain compensation changes the band offsets, and hence modifies the band structures and improves the features of strain- compensated multiple quantum well optoelectronic devices.
In the paper a interferometric sensor for measuring temperature by means of liquid-core fiber is described. The experimental results and theoretical calculations show that a temperature variation of 10-4 degrees C can be measured. We have developed a liquid-core multimode fiber. The liquid-core fiber are composed of hollow silica filled of chlorobenzene. High sensitivity is achieved by the interferometric measuring. It can profitably be employed in spectrum research and sensing.
ZnS, ZnS:Cu and ZnS/CdS nanocrystals were synthesized in polymer matrices with a variety of methods. TEM, absorption spectra and small-angle x-ray scattering studies showed that the particle sizes of ZnS, ZnS:Cu and ZnS/CdS nanocrystals were 3.0, 3.2 and 2.0 nm respectively. Electron diffraction results showed that the ZnS and CdS nanocrystals have the hexagonal structures and Cu ions existed in ZnS with the form of Cu2S. A hole transport material tetraphenylbenzidine (TPB) were also doped into ZnS nanocrystals/polymer to improve the electroluminescent (EL) property of the ZnS nanocrystals. ZnS:Cu, ZnS/CdS and TPB/ZnS nanoparticles/polymer composite as emitters were used to fabricate a single layer structure light-emitting diode between ITO and Al electrodes respectively. The photoluminescence and EL properties of these doped systems were studied. These EL devices had low turn on voltage and the blue electroluminescence from Cu:ZnS and ZnS/CdS and a violet-blue electroluminescence from TPB:ZnS were observed respectively at room temperature under ambient air. The EL mechanism is also discussed.
Electroluminescent (EL) devices were fabricated using Poly(N-vinylcarbazole) (PVK) doped with two high fluorescence blue dyes, 1,1,4,4-Tetraphenyl-1,3-butadiene (TPB) and 2,5-Bis(5-tert-buty 1-2-benzoxazoly) thiophene (BBOT) as an emitting layer, a layer of tris(8-quinolinolato aluminum (III) (Alq3) as an electron-transporting layer, and aluminum as the electron-injecting top electrode contact. The cell structure of glass substrate/ITO/doped PVK/Alq3/Al was employed. In this cell structure, electron and hole are injected from the aluminum electrode and positive polarity, respectively. Then transport into emitting layer and recombinate concomitant electroluminescence from the doped PVK layer. The EL device has a relatively low turn-on voltage of 4 V dc bias, and a luminance of 1200 cd/m2 were achieved at a drive voltage of 10 V. The blue emission peaking at about 455 nm and 475 nm.
Electroluminescence (EL) is reported from a novel polymer blend of poly(2,5-dibutoxyphenylene) (PPP) and polymer poly(N-vinylcarbazole) (PVK). Since PPP and PVK are soluble in common organic solvents, light-emitting diodes (LEDs) can be fabricated by spin-coating films of the polymer blends from solution without subsequent processing or heat treatment. Indium-tin-oxide (ITO) and aluminum (Al) are used as the hole-injection and electron-injection electrodes, respectively. Blue light emission is observed at about 8 V and have a peak emission wavelength at 448 nm at room temperature. The EL efficiency is about 0.82%, which is greater than.that of pure PPP by approximately one order of magnitude.
In this paper, the valence band spin-splitting for the strained superlattices composed of AlyGa1-yAs, AlxGa1-xAs and GaAs was studied. By varying the material compositions or the layer thickness, we observed that the subbands corresponding to the spin-up and spin-down split when the superlattices unit-cell is asymmetrical about the cell center. The spin-splitting is defined as the splitting for both spin-up and spin-down in a spin degenerate subband. Moreover, the splitting mainly occurs at the region where the heavy hole and light hole interact on each other strongly.
A general optoelectronics integrated circuit (OEIC) computer-aided analysis software--OCAP has been developed on Sun SPARC workstations. This system can be used to simulate the DC, AC and transient characteristics of OEIC which can include semiconductor laser diodes such as DH-LD, QW-LD, DFB-LD, detectors such as PIN-PD, PIN-APD, MSM-PD, PINIP two color detector, electronic devices such as diode, B/T, HBT, MESFET, and other basic elements such as resistance, capacitance, inductance, individual source, and controlled source.
Low operating voltage organic molecule dye doped polymers blue electroluminescent (EL) devices were constructed by using air stable aluminum as cathode 1,1,4,4,-tetraphenyl- 1,3-butadiene (TPB) doped poly (N-Vinylcarbazole) (PVK) was used as the light emitting layer, and a layer of tris(8- quinolinolate)-Aluminum(Alq3) film worked as an electron-transporting layer. A device with two layer structure of indium-tin-oxide(ITO)/TPB:PVK/Alq3/Al was obtained. Blue emission began at DC bias voltage of 3.5 V, and blue electroluminescence of 500 cd/m2 was observed at about 10 V, the EL peak was at 449 nm. By using Al as cathode, 2-(4-biphenylyl)-5-(4-terbutypheny)-1-3,4- oxadiazole(PBD) as hole-blocking layer, the device with the structure of ITO/TPB:PVK/PBD/Alq3/Al was also fabricated. Blue emission began at 4 V, more than 1000 cd/m2 was observed at 14 V. These are among the lowest known operating voltage for polymeric EL devices using air stable electrodes. The characteristics of these two kinds of structure devices have also been investigated.
In this report, InGaAs/InGaAsP separated confinement strained-layer multiple-quantum-well laser structures for 1.48micrometers emission wavelength have been grown by LP-MOVPE. The lasing characteristics of the dependence of threshold current densities on the inverse of cavity length and the dependence of threshold current on the cavity length have been studied with room temperature pulse operated broad-area lasers. To reduce the threshold current, the room temperature CW H+ ion implantation stripe lasers with varies widths have been fabricated. The stripe width dependence of threshold current for a set of these devices have also been investigated. Besides, to obtain a high output power from the front facet, we have studied the design of the facet reflective.
Some conclusions have been drawn from the growth of KCl and AgCl optical fiber in the present paper. There is a temperature region with gradient near the solid-melt interface. The phase change latent heat is transmitted by the grown crystal. According to thermal transmission equation, the thermal conductivity (TC) in crystal, Ks, and that in melt, Km, near the solid-melt interface affect strongly on the temperature gradient along the grown axis in crystal and melt. Generally, thermal conductivity in crystal Ks is greater than that in the melt, Km. Similarly, K (metal) > K (nonmetal). TC of non-conducting crystal and metal will reduce with temperature increased TC in conducting liquid is 10 - 1000 times greater than that of non-conducting liquid. Halide ionic crystal with NaCl-type structure is nonconductor, whose TC Ks 1/T, in vicinity of melting point. However halid melt is conducting and its TC, Km, increases as greatly as to transcend the value of Kg. Therefore the temperature gradient in crystal is inevitably greater than that in melt near the solid-melt interface.
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