A U Ubale
Articles written in Bulletin of Materials Science
Volume 28 Issue 1 February 2005 pp 43-47 Thin Films
Zinc sulfide thin films have been deposited onto glass substrates by chemical bath deposition. The various deposition parameters such as volume of sulfide ion source, pH of bath, deposition time, temperature etc are optimized. Thin films of ZnS with different thicknesses of 76–332 nm were prepared by changing the deposition time from 6–20 h at 30°C temperature. The effect of film thickness on structural and electrical properties was studied. The electrical resistivity was decreased from 1.83 × 105 𝛺-cm to 0.363 × 105 𝛺-cm as film thickness decreased from 332 nm to 76 nm. The structural and activation energy studies support this decrease in the resistivity due to improvement in crystallinity of the films which would increase the charge carrier mobility and decrease in defect levels with increase in the thickness.
Volume 29 Issue 2 April 2006 pp 165-168 Thin Films
Structural, electrical and optical characteristics of CdTe thin films prepared by a chemical deposition method, successive ionic layer adsorption and reaction (SILAR), are described. For deposition of CdTe thin films, cadmium acetate was used as cationic and sodium tellurite as anionic precursor in aqueous medium. In this process hydrazine hydrate is used as reducing agent and NH4OH as the catalytic for the decomposition of hydrazine. By conducting several trials optimization of the adsorption, reaction and rinsing time duration for CdTe thin film deposition was done. In this paper the structural, optical and electrical properties of CdTe film are reported. The XRD pattern shows that films are nanocrystalline in nature. The resistivity is found to be of the order of 4.11 × 103 𝛺-cm at 523 K temperature with an activation energy of ∼ 0.2 eV. The optical absorption studies show that films have direct band gap (1.41 eV).
Volume 29 Issue 4 August 2006 pp 413-416 Thin Films
This paper describes the results of thermally stimulated discharge conductivity study of activated charcoal–polyvinyl chloride (PVC) thin film thermoelectrets. TSDC has been carried out in the temperature range 308–400°K and at four different polarizing fields. Results are discussed on the basis of mobility of activated charcoal and polyvinyl chloride chains.
Volume 30 Issue 2 April 2007 pp 147-151 Thin Films
ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S2- and Zn2+ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the wavelength range 250–750 nm show that band gap energy of ZnS increases from 3.68–4.10 eV as thickness varied from 332–76 nm. The structural estimation shows variation in grain size from 6.9–17.8 nm with thickness. The thermoemf measurement indicates that films prepared by this method are of 𝑛-type.
Volume 30 Issue 2 April 2007 pp 163-166 Polymers
The electrical conductivity of naphthalene doped polystyrene (PS) films (≈ 61.58 𝜇m thick) was studied as a function of dopant concentration and temperature. The formation of charge transfer (CT) complexes and strong concentration dependence of carrier mobility point out that the current carriers are transported through doped polymer system via hopping among sites associated with the dopant molecules. The activation energy, 𝐸a, was calculated from the graph of log𝜎vs 103/𝑇 plot within low and high temperature regions.
Volume 42 | Issue 6
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