Structure, optical and electrical properties of ZnSe thin films

ZnSe thin films were prepared by the vacuum evaporation technique. The influence of substrate temperature on compositional, structural, optical and electrical properties of polycrystalline ZnSe films was investigated using Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), Scanning electron microscopy (SEM), optical transmission and DC conduction studies. The composition analysis shows the nearly stoichiometric nature of the deposited film. The X-ray diffractograms reveals the cubic structure of the film oriented along the (1 1 1) direction. The structural parameters such as particle size [28.41-50.24 nm], strain [1.381-0.785×10^-3 lin^-2 m^-4] and dislocation density [1.285-0.412×10¹⁵ lin m^-2] were evaluated. Optical transmittance measurements indicate the existence of direct allowed optical transition with a corresponding energy gap in the range of 2.72-2.60 eV. In the DC conduction studies the conduction mechanism is found to be exponential trap distribution and the results are discussed.