Synthesis and characterization of nano-structured Se77Sb15Ge8 thin films

Abstract

Amorphous nano-structured thin films have made great attention because of its enormous importance for the development of nano-technology. The present research paper describes the synthesis and characterization of Se77Sb15Ge8 nano-structured thin films. By melt quench techniques, bulk Se77Sb15Ge8 material was put in order whose amorphous nature was confirmed by XRD and non-isothermal DSC measurements. Thin films (nano-structured) of amorphous Se77Sb15Ge8 material were made by physical vapor condensation technique. To examine the surface morphology of thin films, scanning electron microscope was employed. The average particle size lies in the range 30–60nm. The detailed examination of the data of optical absorption points out that the optical transition is indirect in nature. The optical band gap is viewed around 1.53eV. The dark conductivity of nano-structured Se77Sb15Ge8 thin films was also studied at various temperatures in the range 313–463K in the steps of 5K. It is noticed that the dark conductivity tends to increase with increasing temperature. Our experimentation data advocates that the conduction is owing to thermally supported channeling of the charge carriers in the confined states close to the band edges. The dc activation energy in nano-structured Se77Sb15Ge8 thin films is found to be 1.23eV. A good agreement has been obtained between the estimates of activation energy and optical band gap.