B.K. Samantaray

Effect of plasticizer on microstructure and electrical properties of a sodium ion conducting composite polymer electrolyte

A plasticized composite polymer electrolyte (PCPE) based on Poly (ethylene oxide) + NaI with Na2SiO3 as the ceramics filler and Poly (ethylene glycol) as the plasticizer has been prepared by solution cast technique. Effect of plasticization on microstrucutre and electrical properties of the materials has been investigated. The changes in the structural and microstructural properties of the material have been investigated by XRD and SEM studies. The electrical conductivity estimated using a. c. impedance spectroscopy was found to be dependent on plasticizer concentration. An enhancement in the ionic conductivity value by three times has been recorded on addition of plasticizer when compared with that of unplasticized composite polymer electrolyte. The temperature dependence of conductivity of the polymer films is found to obey the Arrhenius behavior below and above the melting temperature of PEO. The electrical transport has been found to be a thermally activated process with ions being the predominant charge carrier.

Structural characterization of cadmium selenide thin films by X-ray diffraction and electron microscopy

X-ray diffraction, transmission electron microscopy and transmission electron diffraction studies on cadmium selenide thin films deposited on glass substrates have been carried out. X-ray line profile analysis of the diffraction panems has been performed to study the microstructural parameters. The variation of different microstructural parameters. such as crystallite size, RMS strain. dislocation density and stacking fault probability with film thickness as well as substrate temperature is studied. The optimum growth condition is fixed to a film thickness of the order of 1 .Opm. The change of preferred orientation is observed for films deposited at and above 473 K. 0

Structural characterization of thin films of cadmium telluride

Abstract X-ray diffraction patterns of vacuum-deposited thin films of cadmium telluride have been recorded and X-ray line profile analysis studies have been carried out after correcting for instrumental broadening. Size of the crystallites, r.m.s. strain, dislocation density and stacking fault probabilities have been estimated using the method of variance analysis and peak shift of the line profiles. It is observed that with increase in the thickness of the films there is an increase in the stacking fault probability and this inhibits the growth of the crystallites and results in the increase in r.m.s. strain and dislocation density. The photosensitivity of the films is measured and it is observed, that at about 400 nm thickness, the photosensitivity is at a maximum. An attempt is made to correlate the results.

Effect of substrate temperature on SnTe films

Vacuum deposited thin films of SnTe on mica and glass substrates have been studied at substrate temperatures between 300 and 498K by X-ray, electron diffraction and electrical measurements. It has been observed that at an optimum substrate temperature of 448K the films have maximum mobility, carrier concentration and crystallite size. Films deposited on glass and mica substrates have most of the crystallites aligned with their (100) and (111) planes parallel to the substrate.

Effect of preferred orientation on photovoltage of CdTe thin films

Abstract Photovoltaic property of angularly deposited CdTe films is studied by the X-ray diffraction. The variation of photovoltage of the film deposited at different angles and different substrate temperatures are co-related with the preferential orientation of the crystallites. The magnetude of the photo-e.m.f. developed is dependent on the relative number of planes having {220} and {311} orientation and corresponding optical absorption.

X-ray diffraction and electron microscopic studies on selenium substituted indium intercalation compounds of tungsten disulphide

Abstract Selenium substituted indium intercalation compounds of tungsten disulphide, In 1/3 WS 2− x Se x (0≤ x ≤2) have been studied for microstructural characterization using X-ray line profile analysis to find out information about crystallite size, r.m.s. strain, dislocation density, variability of interlayer spacing, fraction of planes affected by such defects, stacking fault probability, crystallite size anisotropy etc. Scanning electron microscopic (SEM) and scanning tunneling microscopic (STM) studies are also reported herewith. These results have also been compared with respect to the pure WS 2− x Se x (0≤ x ≤2).

The phenomena of photoconductivity and long-term photorelaxation in indium selenide thin films

The variation of photoconductivity with temperature and long-term photorelaxation under weak and moderate illuminations in polycrystalline InSe thin films are studied. Different decay characteristics are determined and it is found that separate barriers are responsible for drift and recombination. The long-term photodecay is found to be exponential with time for weak illumination. The photosensitivity of the films is also determined and its variation with temperature is studied.

X-ray studies on the structure of p-(Pb1−xSnx)1−y Tey thin films

Thin films were deposited by vacuum evaporation of p-(Pb1−xSnx)1−y Tey powders (where x ≃ 0.71 and y ≃ 0.508) on to glass, mica and natural NaCl substrates heated to various temperatures. X-ray diffractograms show that films deposited on colder substrates exhibit inferior crystalline quality. Films deposited at Tsub ≃ 457±5 K are polycrystalline, showing strong (2 0 0) or (2 2 2) peaks along with weaker (2 2 0), (4 0 0) or (4 2 0) peaks. Variance analyses performed on intense line profiles show that the crystallite size, r.m.s. strain and dislocation density are fairly high even in polycrystalline films. PbSnTe crystallites show a preference for (1 0 0)-oriented growth on heated glass and (1 0 0)-cleaved NaCl substrates; but on equally heated mica, their growth shows an initial preference for the (1 1 1) orientation, which gradually switches over to the (1 0 0) orientation for higher thicknesses. Probably due to a higher SnTe content, PbSnTe crystallites show evidence of misorientation on heated glass and natural NaCl substrates.

X-ray and electron microscopic determination of Debye characteristic temperature, stacking fault energy and other microstructural parameters in zinc telluride films

X-ray diffraction, transmission electron microscopy and transmission electron diffraction have been performed on polycrystalline zinc telluride films deposited on glass substrates at different conditions. Along with the cubic phase, the hexagonal phase is detected in the films deposited at 623 Κ and higher substrate temperatures. Lattice parameters of both phases are calculated from X-ray diffraction and TED data and their variation with the film thickness and substrate temperatures are studied. Cation — cation distances in films of the cubic phase are calculated. Stacking fault energy and Debye characteristic temperature in ZnTe films, their variations with film thickness and substrate temperature are reported for the first time. Attempts have been made to explain the variations in terms of existing theories.

X-RAY, ELECTRON MICROSCOPY AND PHOTOVOLTAIC STUDIES ON CDTE THIN FILMS DEPOSITED NORMALLY AT DIFFERENT SUBSTRATE TEMPERATURES

X-ray diffraction, transmission electron microscopy and electron diffraction studies were conducted on CdTe thin films deposited on glass substrates kept at different substrate temperatures. Variation of the different structural parameters, such as lattice constant, crystallite size, r.m.s. strain, dislocation density and stacking fault probability with substrate temperature, was investigated in the temperature range 300 to 498 K. An increase in the lattice constant and crystallite size values and a decrease in the other parameters with increase in temperature of the substrate was observed. A photovoltage was observed for CdTe film deposited normally on glass substrates kept at higher substrate temperatures. The development of photovoltage in the film is explained in the light of the formation of crystallites of variable structure.