Carbon nanotube (CNT) films deposited on different porous silica substrates were studied by Scanning Electron Microscopy (SEM) and Raman Spectroscopy (RS). The films samples were prepared by a two-step method consisting of PVD and CVD processes. In the first step the nanocomposite Ni-C film was obtained by evaporation in dynamic vacuum from two separated sources of fullerenes and nickel acetate. Those films were deposited on porous silica and DLC/porous silica substrates. Analysis of SEM imaging showed that the obtained film are composed of carbon nanotubes, the distribution, size and quality of which depend on the type of substrate. The CNT films were studied by RS method to determine the influence of the substrate type on disordering of carbonaceous structure and quality of CNT in deposited films.
The TiO2 coatings were prepared by simple sol-gel method and modified by UV pulsed laser. TiO2, also know as titania, is a ceramic compound, existing in numerous polymorphic forms, mainly as tetragonal rutile and anatase, and rhomboidal brookite. Rutile is the most stable form of titanium dioxide, whereas anatase is a metastable form, created in lower temperatures than rutile. Anatase is marked with higher specific surface area, porosity and a higher number of surface hydroxyl groups as compared to rutile. The unique optical and electronic properties of TiO2 results in its use as semiconductors dielectric mirrors, sunscreen and UV-blocking pigments and especially as photocatalyst.
In this paper, the tetraisopropoxide was used as Ti precursor according to sol-gel method. An organic base was applied during sol preparation. Prepared gel was coated on glass substrates and calcined in low temperature to obtain amorphous phase of titania. Prepared coatings were modified by UV picosecond pulse laser with different pulse repetition rate and pulse power. Physical modification of the coatings using laser pulses was intended in order change the phase content of the produced material. Raman spectroscopy (RS) method was applied to studies of modified coatings as it is one of the basic analytical techniques, supporting the identification of compounds and obtaining information about the structure. Especially, RS is a useful method for distinguishing the anatase and rutile phases. In these studies, anatase to rutile transformation was observed, depending on laser parameters.
Titanium oxide displays, among others, catalytic and bactericidal properties, as well as the capacity to absorb UV radiation. The properties may differ significantly depending on the phase composition. This is why for the prospective applications it is necessary to determine the effect of the obtaining process parameters on the phase composition and, consequently, on the properties of the obtained samples. In our work we present results of Raman spectroscopy and X-ray diffraction studies of TiO2 layers obtained in sol-gel method. The work will present effects of calcination temperature on the structure of the obtained layers. Raman Spectroscopy is a useful method of identification, allowing to distinguish the anatase phase from the rutile phase.
In this paper the preparation process and optical characterization of pure and Al3+ doped zinc oxide (Al:ZnO) coatings will be presented. ZnO based materials have been studied extensively due to their potential applications in optoelectronic devices as conductive gas sensors, transparent conductive, electrodes, solar cell windows, varistors, UVfilters or photovoltaic cells. It is II–VI semiconductor with wide-band gap of 3.37 eV and large exciton binding energy of 60meV. It is possible to improve the conductivity of ZnO coating by intentionally doping ZnO with aluminium ions during preparation process. Such transparent and conducting thin films, known as AZO (Aluminium Zinc Oxide) films, are very good candidate for application as transparent conducting materials in many optoelectronic devices. The well-known sol-gel method is used for preparation of solution, coated on glass substrates by dip coating process. Prepared samples were investigated by Raman and UV-VIS spectroscopy. Transmittance as well as specular and diffuse reflectance spectroscopy methods were used for studies of optical parameters. We found that Al admixture influences on optical bandgap of ZnO.
The thin films of carbon-nickel (C-Ni) nanocoposites were deposited on Ti-evaporated Si (100) substrate using Physical Vapour Deposition (PVD) method. Influence of evaporated titanium on carbonaceous structure of C-Ni films were investigated by Raman spectroscopy method. The fullerite-graphite structure was recognize using principal component analysis (PCA) of obtained Raman spectra.
In this paper influence of hydrogen on molecular structure of carbonaceous-palladium (C-Pd) films using Raman and
FTIR spectroscopy methods has been studied. The special experimental setup (gas cell) was design and realized. The
spectra were measured in H2/N2 atmosphere under different gas pressure and flow rate and compared with base spectra
measured in air. The noticeable influence of gas flow on intensity of some bands in FTIR spectra were observed.
Understanding of role of H2 in interaction with C-Pd film needs other experimental works. Observed phenomenon can
be used in construction of optical hydrogen sensor.
In the studies presented we proposed a new application for nanocomposite carbon films (C-Pd). These films were
evaluated as an anode material for Microbial Fuel Cells (MFCs) used for electrical current generation. The results of
characterization of C-Pd films composed of carbon and palladium nanograins were obtained using the Physical Vapor
Deposition (PVD) method. The film obtained by this method exhibits a multiphase structure composed of fullerene
nanograins, amorphous carbon and palladium nanocrystals. Raman Spectroscopy (RS) and scanning electron microscopy
(SEM) are used to characterize the chemical composition, morphology and topography of these films.
We observed, for MFC with C-Pd anode, the highest electrochemical activity and maximal voltage density - 458 mV
(20,8 mV/cm2) for Proteus mirabilis, 426 mV (19,4 mV/cm2) for Pseudomonas aeruginosa and 652 mV (29,6 mV/cm2)
for sewage bacteria as the microbial catalyst.
We present results of Raman studies of CNT-Ni films obtained in two steps method. In the first step an initial
nanocomposite Ni-C film (produced by PVD method) was prepared. This initial film has multiphase composite-like
structure with nanograins of fullerenes, amorphous carbon and nickel. In the second step CNTs were obtained by CVD
method. In this process the initial films were placed in a quartz tube reactor where pyrolysis process were performed in
xylene. Decomposition of xylene at 650°C was occurred. Products of this CVD decomposition process take part in
nanotubes growth on Ni nanograins. These nanograins play a role of a catalyser of the growth process. SEM
observations showed that form of nanotubes obtained with the various CVD process parameters is similar.
Raman studies of initial films (obtained PVD process) confirm the presence of fullerenes C60 in and some forms of
graphite–like objects in the samples. Raman spectra of MWCNTs films contained: bands characteristic for carbon
The results of Raman and SEM studies of Pd-carbonaceous films obtained by two methods are presented in this paper.
The first method is PVD (Physical Vapour Deposition) with two separated sources containing precursors for films (1 -
fullerenes C60, 2- palladium acetate). The second method consists of two steps, the first step being PVD followed by
CVD (Chemical Vapour Deposition) - the second step. In the first step a nanocrystalline Pd-C film is prepared. Later this
film is used to obtain a nanoporous Pd - carbonaceous film in the CVD process. Prepared films contain 8 - 34 %wt. Pd.
Both kinds of films were studied using Raman and SEM methods. For the films obtained in the two-step method SEM
images show porous structure for all samples. Raman spectra for the film with 8 % wt. Pd exhibit C60 characteristic
bands, while Raman spectra for films with higher content of Pd show D and G graphite characteristic bands. Films
obtained by PVD are structurally different from films obtained by 2-steps method which is reflected in SEM images
where no porous structure has been found.
The paper presents preparation of film composed of Pd nanocrystals embedded in carbonaceous matrix and
characterization of their characteristics, such as structure and optical properties. Pd nanocrystalline films were obtained
by the physical vacuum deposition method (PVD) and were studied by TEM, AFM and optical absorption (UV-VIS
absorption) methods. Pd nanocrystals have structure of fcc type and are embedded in matrix based on fullerene structure
of fcc type. The interaction between Pd and elements of carbon matrix interface were studied by UV-VIS absorption
The characterization NiN nanocrystals (N- number of atoms in a nanocrystal) embedded in carbonaceous matrices is presented. The physical vapor deposition method was used to prepare nanocrystals. Transmission electron microscopy (TEM), atomic force microscopy (AFM), chemical analysis methods and optical absorption spectroscopy have been used to study samples properties. A hypothetical structure of nanocrystals NiN (13
Wavelet transform method is developed independently in the fields of mathematics, quantum physics, electrical engineering, and seismic geology from a several decades. The wavelets are mathematical functions that cut up data into different frequency components, and then study each component with a resolution matched to its scale. This method is more useful than traditional Fourier methods, when the signal contains discontinuities and sharp spikes. Interactions between different scientific fields have led to many new wavelet applications such as image compression, turbulence, human vision, radar, and earthquake prediction. This paper is dedicated to possibility of using the wavelet transform in some optical research method i.e. interference images analysis. Special attention is paid to noise detection in these images.