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Structural, optical and electrical characterization of CBD synthesized CdO thin films: influence of deposition time

Das M.R., Mukherjee A., Mitra P.

Materials Science Poland

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2017

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Vol. 35, No. 3

470--478

EN

Cadmium oxide (CdO) thin films were grown on glass substrates by chemical bath deposition (CBD) method for different deposition times using cadmium acetate as cationic precursor. The structural and optical characterization was carried out using XRD, TEM, and UV-Vis spectrophotometer measurements. Structural analyses with XRD confirmed cubic structure of the CdO. Average particle size estimated from Rietveld refinement method of XRD pattern corresponded well with TEM measurement. The optical band gap varied between 2.35 eV to 2.48 eV with deposition time and an increase in optical band gap with decreasing film thickness was observed. The AC electrical conduction behavior of the CdO film was investigated as a function of temperature as well as frequency. The conductivity measurements indicated localized conduction and hopping of carriers between localized states. The value of real part of dielectric constant was found to decrease with frequency and increase with temperature. The Nyquist plots at different temperatures showed the existence of both grains and grain boundaries contributing to conduction mechanism.

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Structural and optical characteristics of SnS thin film prepared by SILAR

Mukherjee A., Mitra P.

Materials Science Poland

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2015

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Vol. 33, No. 4

847--851

EN

SnS thin films were grown on glass substrates by a simple route named successive ion layer adsorption and reaction (SILAR) method. The films were prepared using tin chloride as tin (Sn) source and ammonium sulfide as sulphur (S) source. The structural, optical and morphological study was done using XRD, FESEM, FT-IR and UV-Vis spectrophotometer. XRD measurement confirmed the presence of orthorhombic phase. Particle size estimated from XRD was about 45 nm which fitted well with the FESEM measurement. The value of band gap was about 1.63 eV indicating that SnS can be used as an important material for thin film solar cells. The surface morphology showed a smooth, homogenous film over the substrate. Characteristic stretching vibration mode of SnS was observed in the absorption band of FT-IR spectrum. The electrical activation energy was about 0.306 eV.

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Hydrogen and LPG sensing properties of SnO2 films obtained by direct oxidation of SILAR deposited SnS

Mitra P., Mondal S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2008

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Vol. 56, nr 3

294-312

EN

Hydrogen (H2) and liquid petroleum gas (LPG) sensing properties of SnO2 thin films obtained by direct oxidation of chemically deposited SnS films has been studied. The SnS film was prepared by a chemical technique called SILAR (Successive Ionic Layer Adsorption and Reaction). The sensor element comprises of a layer of chemically deposited SnO2 film with an overlayer of palladium (Pd) sensitiser. The Pd sensitiser layer was also formed following a chemical technique. The double layer element so formed shows significantly high sensitivity to H2 and LPG. The temperature variation of sensitivity was studied and the maximum sensitivity of 99.7% was observed at around 200°C for 1 vol% H2 in air. The response time to target gas was about 10 seconds and the sensor element was found to'recover to its original resistance reasonably fast. The maximum sensitivity of 98% for 1.6 vol% LPG was observed at around 325°C. The sensor response and recovery was reasonably fast (less than one minute) at this temperature.

4

ZnO thin film as methane sensor

Mitra P., Mukhopadhyay A.K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2007

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Vol. 55, nr 3

281-285

EN

Methane (CH4) sensitivity of zinc oxide (ZnO) thin film has been studied in the present work. The sensor element comprises of a chemically fabricated ZnO semiconducting layer and a layer of palladium (Pd) as catalyst. The catalyst layer was formed on the surface of semiconducting ZnO following a wet chemical process from palladium chloride (PdCl2) solution. Fundamental features of a sensor element e.g. sensitivity, response time and recovery process has been studied. The effect of operating temperature on performance of the sensor material has been investigated and a choice of optimum temperature was made at around 200°C. The sensor element exhibited reasonable sensitivity of about 86% at this temperature in presence of 1 vol% methane (CH4) in air.