Structural and Optoelectronic Properties of Nanocrystalline CdTe Thin Films Synthesized by Using SILAR Technique

Abstract

Nanocrystalline CdTe thin films were deposited on amorphous glass substrate using successive ionic layer adsorption and reaction (SILAR) technique. The films are characterized using XRD, FESEM, optical absorption techniques and electrical resistivity measurement. The XRD pattern revealed that nanocrystalline CdTe thin films has mixed phase of hexagonal and cubic crystal structure. The calculated crystallite size from the XRD measurement was found to be in the range of 9-12 nm. FESEM image showed uniform deposition of the material over entire glass substrate and film consists of interconnected spherical grains of nanometer size. Compositional analysis showed that the nanocrystalline CdTe thin film becomes cadmium deficient and tellurium richer. The optical absorption studies show that the films have a direct band gap of 1.51 eV. The room temperature resistivity of the synthesized nanocrystalline CdTe films measured by two probe method was found to 6.64 × 104 Ω.cm.