The Effect of Annealing Temperature on the Optical Properties of the a-Gc: As Thin Films

a-Ge: As thin films have prepared by thermal evaporation technique, then they were annealing at various temperatures within the range (373-473) K. The result of X-ray diffraction spectrum was showing that all the specimens remained in amorphous structure before and after annealing process. This paper studied the cffcct of annealing temperature as a function of wavelength on the optical energy gap and optical constants for the a-Ge:As thin films . Results have showed that there was an increasing in the optical energy gap (Eg0pl) values with the increasing of the annealing temperatures within the range of measurements due to the decrease in defect states near the bands. The refraction index . real and imaginary parts of dielectric constant and the extinction coefficient decrease with the increasing of the annealing temperatures.