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Structural, optical, morphological and electrical properties on PbSe bi-layer thin films

V.Arivazhagan, M.Manonmani Parvathi, S.Rajesh

The bi-layer thin films of PbSe were prepared by successive coatings of Lead and Selenium layers by thermal evaporation technique. The temperature of the substrate was varied from low (0 C) to high (100C) and its structural, optical and electrical propertieswere studied usingXRD, UV and Hall measurement system respectively. X-ray analysis exhibits the polycrystalline nature of the prepared films with cubic structure. The relatively strongest intense peak corresponding to (2 0 0) plane for PbSe was investigated. The optical study reveals that the absorption edge starts with lower wavelength and indicates the formation and presence of PbSe nanoparticle at the interface of Lead and seleniumlayers. The calculated band gap values vary from3.35 to 3.75 eV which ismuch larger than the bulk band gap value of PbSe material. The scanning electron microscopic images show the surface morphology of the Pb-Se bilayer films and the nano needle like structure was observed on low temperature substrate films. The carrier concentration andmobility of the films varied from3.244X1011 cm-2 to 107X1011 cm- 2 and 0.197X101cm2/Vs to 23.17X101cm2/Vs respectively. The sheet resistance of the films varied from0.416 to 3.198X102/sq and the resistivity also reported in this paper.