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

Abstract

a-Ge: As thin films have prepared by thermal evaporation teclmique, then they were annealing at various temperatures within the

range (373-473)  K.   The  result of  X-ray di ffraction spectrum  was showing  that  all  the  specimens  remained  in  amorphous structure before and after annealing  process. This paper studied the effect 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

{Egopt) values with the in ,;rcasing 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 i.ncrellsing of the annealing temperatnres .