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Item Investigations on electrical properties of the CdxZn 1-xS thin films prepared by spray pyrolysis technique(2011) Raviprakash, Y.; Bangera, K.V.; Shivakumar, G.K.Thin films of CdxZn(1-x)S (0≤x≤1) were deposited on glass substrates by the chemical spray pyrolysis technique. The electrical properties of these films in relation with composition were studied in detail. The entire investigation was made for a wide range of compositions of CdxZn(1-x)S thin films (x=0 to 1 in steps of 0.1). The variations of conductivity and current-voltage characteristics of these films were investigated as a function of the temperature and applied voltage. The activation energy of the films was found to vary from 0.35 eV to 0.78 eV. © 2011 American Institute of Physics.Item Semiconducting thin films of cadmium selenide have been grown by conventional thermal evaporation technique. The effect of various growth parameters like rate of deposition and deposition temperature has been studied in detail. Films deposited at room temperature are cadmium rich with segregated selenium globules. A deposition temperature of 453K has been found to yield stoichiometric, homogeneous films. The films have been analysed for optical band gap and thermal activation energies. Films of low electrical resistivity have been obtained for possible applications.(Growth and characterization of semiconducting cadmium selenide thin films) Shreekanthan, K.N.; Rajendra, B.V.; Kasturi, V.B.; Shivakumar, G.K.2003Item Semiconducting thin films of cadmium telluride, both p-type and n-type, have been prepared by conventional thermal evaporation technique. The influence of various growth parameters such as the rate of deposition, deposition temperature, post-deposition heat treatment, and source material composition has been investigated. The films deposited at high deposition rates and low substrate temperatures exhibited an excess of tellurium and showed a p-type conductivity, whereas those deposited at high substrate temperature and low deposition rates contained excess cadmium and are n-type in nature. An intrinsic bandgap of 1.49 eV for stoichiometric films obtained by both electrical and optical characterization is reported.(Growth and characterization of vacuum deposited cadmium telluride thin films) Shreekanthan, K.N.; Kasturi, V.B.; Shivakumar, G.K.2003Item Photoconductivity has been studied in cadmium selenide thin films prepared by thermal evaporation in vacuum. Attempts have been made to correlate the photoresponse with the deposition conditions. It has been observed that as-grown films, irrespective of the cadmium content, are not photosensitive and that baking in air, especially above 723 K, leads to considerable improvement in the photoconducting properties of cadmium selenide films.(Photoconductivity in vacuum deposited cadmium selenide thin films) Rajendra, B.V.; Kasturi, V.B.; Shivakumar, G.K.2004Item Structure and properties of vacuum deposited cadmium telluride thin films(2006) Shreekanthan, K.N.; Bangera, K.V.; Shivakumar, G.K.; Mahesha, M.G.Systematic and detailed study of the growth and properties of vacuum deposited cadmium telluride thin films was made. Both p- and n-type films were grown and these films were characterized for their structural, optical, and electrical properties. The crystallographic structure of the deposits was found to be dependent on the rate of deposition. Low deposition rates were observed to result in hexagonal deposits whereas high rates of deposition favoured cubic structure for the film. Electrical and optical properties were also found to be dependent on the deposition parameters.Item Characterization of thin film Al/p-CdTe schottky diode(2008) Mahesha, M.G.; Kasturi, V.B.; Shivakumar, G.K.A study has been made on the behavior of Al/p-CdTe thin film junction grown by thermal evaporation method. I-V characteristics show that the Al makes Schottky contact with p-CdTe. The variation of junction capacitance with frequency and voltage has been studied to evaluate the barrier height. The activation energy and band gap have been estimated by studying variation of resistivity with temperature. Using all these data, band diagram of Al/p-CdTe has been proposed. © TÜB?TAK.Item The effect of substrate temperature on the structural, optical and electrical properties of vacuum deposited ZnTe thin films(2009) Rao, G.K.; Bangera, K.V.; Shivakumar, G.K.The present paper reports the effect of substrate temperature on the structural, optical and electrical properties of vacuum deposited zinc telluride (ZnTe) thin films. X-ray diffraction (XRD) analysis of the films, deposited on glass substrates, revealed that they have cubic structure with strong (111) texture. Room temperature deposits are tellurium rich and an increase in the substrate temperature up to 553 °K results in stoichiometric films. Electrical conductivity has been observed to increase with the increase in substrate temperature, accompanied by increase in the carrier concentration and the mobility of the carriers. The optical bandgap energy and the thermal activation energy of the films have also been evaluated. © 2009 Elsevier Ltd. All rights reserved.Item Preparation and characterization of CdxZn1-xS thin films by spray pyrolysis technique for photovoltaic applications(2009) Raviprakash, Y.; Bangera, K.V.; Shivakumar, G.K.CdxZn(1-x)S (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) thin films were deposited by the chemical spray pyrolysis technique using a less used combination of chemicals. Depositions were done at 573 K on cleaned glass substrates. The composition, surface morphology and structural properties of deposited films were studied using EDAX, SEM and X-ray diffraction technique. XRD studies reveal that all the films are crystalline with hexagonal (wurtzite) structure and inclusion of Cd into the structure of ZnS improved the crystallinity of the films. In the entire compositions, the (0 0 2) diffraction peak is prominent which gives lattice matching to the chalcogenide semiconductor such as CuInxGa1-xSe2 and CuIn (s1-xSex)2, which are used in photovoltaic devices. The value of lattice constant 'a' and 'c' have been observed to vary with composition from 0.382 to 0.415 nm and 0.625 to 0.675 nm, respectively. The band gap of the thin films varied from 3.32 to 2.41 eV as composition varied from x = 0.0 to 1.0. It was observed that presence of small amount of cadmium results in marked changes in the optical band gap of ZnS. © 2009 Elsevier Ltd. All rights reserved.Item Growth, structural and optical properties of CdxZn1-xS thin films deposited using spray pyrolysis technique(2010) Raviprakash, Y.; Bangera, K.V.; Shivakumar, G.K.CdxZn(1-x)S (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) thin films were deposited by the chemical spray pyrolysis technique using a less used combination of chemicals. Depositions were done at 573 K on cleaned glass substrates. The composition, surface morphology and structural properties of deposited films were studied using EDAX, SEM and X-ray diffraction technique. XRD studies reveal that all the films are crystalline with hexagonal (wurtzite) structure and inclusion of Cd into the structure of ZnS improved the crystallinity of the films. The value of lattice constant 'a' and 'c' have been observed to vary with composition from 0.382 to 0.415 nm and 0.625 to 0.675 nm, respectively. The band gap of the thin films varied from 3.32 to 2.41 eV as composition varied from x = 0.0-1.0. It was observed that presence of small amount of cadmium results in marked changes in the optical band gap of ZnS. © 2009 Elsevier B.V. All rights reserved.Item Studies on the photoconductivity of vacuum deposited ZnTe thin films(2010) Rao, K.G.; Bangera, K.V.; Shivakumar, G.K.The present paper reports the analysis of photoconductivity of vacuum deposited zinc telluride (ZnTe) thin films as a function of substrate temperature and post-deposition annealing. Detailed analyses were first carried out to understand the effect of substrate temperature and annealing on the structure, composition, optical and electrical properties of the films. The films deposited at elevated substrate temperatures showed faster and improved photoresponse. Post-deposition annealing was found to further enhance the photoresponse of the films. Attempts have been made to explain the improvement in the photoresponse on the basis of structural and compositional changes, taking place in the films, due to the substrate temperature and annealing. © 2010 Elsevier Ltd. All rights reserved.