ABSTRACT

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Abstract
This study reports the synthesis and characterization of CdSe and CdTe multilayer thin films via Thermal evaporation technique. The multilayer thin films were respectively prepared sequentially at 100 oC in a vacuum of about 2.0 x 10-5 torr and annealed in vacuum at 120 oC for 15 mins. The thickness of Cd was 500 Å while Se and Te were respectively 150 Å. Optical properties were studied using UV-Vis Spectrophotometer. The electrical characterization was carried out using Keithley Four-point Probe. UV-Visible analysis of the film showed a direct optical band gap which is found to be 1.90 eV and 1.00 eV for the CdSe and CdTe films respectively, with an enhanced light absorption in the range of 350 nm to 950 nm (at infra-red region) spectrum. The Electrical results revealed that the CdSe exhibited n-type semi-conductivity because of non-stoichiometry with optimum resistivity of 0.86 x 10-3 Ocm-1 while CdTe exhibited a p-type semi-conductivity. It could be concluded that CdSe is a good material for window layer while CdTe is a good material for absorber in photovoltaic applications.
Keywords: thermal evaporation, optical band gap, electrical conductivity, absorber layer, window layer and photovoltaic application.

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