Browsing by Author "Rao, K.G."

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    Conduction mechanisms in vacuum deposited p-ZnTe/n-Si heterojunction diodes
    (2011) Rao, K.G.; Bangera, K.V.; Shivakumar, G.K.
    p-ZnTe/n-Si heterojunction diodes were prepared by vacuum depositing ZnTe films on n-Si substrates. Detailed electrical characterization was performed to determine the conduction mechanisms operating in the diode. Important parameters such as ideality factor and barrier height were also determined. � 2011 American Institute of Physics.
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    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.
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    Studies on vacuum deposited p-ZnTe/n-CdTe heterojunction diodes
    (2011) Rao, K.G.; Bangera, K.V.; Shivakumar, G.K.
    The present paper reports the fabrication and detailed electrical characterization of p-ZnTe/n-CdTe heterojunction diodes prepared by vacuum deposition method. The possible conduction mechanisms of the heterojunction diode were determined by analyzing the I-V characteristics. The C-V characteristics of the heterojunction diodes were studied to determine the barrier height, carrier concentration and thickness of the depletion region in the heterojunction. A theoretical band diagram of the heterojunction was drawn based on Anderson's model. © 2010 Elsevier Ltd. All rights reserved.
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    Studies on vacuum deposited p-ZnTe/n-ZnSe heterojunction diodes
    (2010) Rao, K.G.; Bangera, K.V.; Shivakumar, G.K.
    p-ZnTe/n-ZnSe heterojunction diodes were prepared by vacuum deposition and a detailed electrical characterization of the heterojunction was performed. The I-V and C-V characteristics of the heterojunction diodes were studied to determine the conduction mechanism, barrier height, space charge density and thickness of the depletion region in the heterojunction. The bandgap and activation energies of n-ZnSe and p-ZnTe were also determined and a theoretical band diagram of p-ZnTe/n-ZnSe heterojunction was drawn based on Anderson's model. © 2010 Elsevier Ltd. All rights reserved.
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    The p-type doping of vacuum deposited ZnTe thin films with bismuth by a new technique of using nano-spheres
    (Elsevier Ltd, 2010) Rao, K.G.; Shivakumar, G.K.; Kasturi, V.B.
    The present paper reports the successful doping of vacuum evaporated zinc telluride (ZnTe) thin films with bismuth by a new technique of using nano-spheres. The discontinuous films of bismuth (the dopant material), containing bismuth in the form of nano-spheres, were prepared by vacuum evaporation and the ZnTe films were then deposited on top of them. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to ascertain the formation of discontinuous bismuth films and the proper diffusion of bismuth in ZnTe films, respectively. After doping, the carrier concentration of the ZnTe films was found to increase by an order of the magnitude. The electrical conductivity also improved significantly. The photoconductivity and photo-response properties of the doped films were also analysed. © 2010 Elsevier B.V. All rights reserved.