Electrical Properties of Thermally Evaporated CdSe and ZnCdSe Thin Films

Cadmium selenide (CdSe) and zinc (Zn) doped cadmium Selenide (ZnCdSe) thin films were deposited onto thoroughly cleaned glass substrates by thermally evaporating CdSe and Zn powders and then laterannealed at 200 °C for 2 h in vacuum. CdSe and ZnCdSe thin films were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive analysis of X-rays (EDAX) and UV-Vis spectroscopy to study the structural, morphological, compositional and optical properties. The XRD patterns showed that the films were polycrystalline in nature. FE-SEM micrographs indicated that the films were smooth and homogeneously distributed. EDAX affirms the presence of Zn, Cd and Se. The optical band gap decreased with increasing thickness. The carrier concentration, current voltage (I-V) characteristics and resistivity of the films were studied using the Hall effect, electrometer and four point probe method. ZnCdSe films exhibited Ohmic behaviour in the range of -10 to +10 V.