Optical properties of amorphous Ga 20Se 80-xBix thin films

摘要

The optical properties of amorphous Ga20Se80- xBix (aGa20Se80- xBix) thin films (where x = 0, 5, 10, 15 and 20) have been studied in the wavelength range (450-1400nm). It is found that the optical bandgap decreases with increasing bismuth content in the a-Ga20Se80- xBix system. The value of the refractive index n decreases, while the value of the extinction coefficient k increases with increasing photon energy. The dc conductivity measurements of a-Ga20Se80- xBix thin films have also been reported in the temperature range 287-318K. It is observed that the activation energy decreases with increase in the metallic impurity in a-(Se-Ga) binary alloys.