The effect of doping process on the structural and optical properties of Ag2Se thin films.

Abstract

Ag2Se alloys have been prepared, thin films of this compound has been deposited by the thermal evaporation method under a vacuum of 10−5 Torr, on coring glass substrate at room temperature. They have a thickness of (500±10) name and rate of deposition (2.07813nm Sec-1). The Ag2Se films has been doped by different elements (Al, Bi, Sb, and Cd) with a constant ratio 2% by thermal diffusion method. The structure of the alloys and the thin films have been examined by the XRD method show that the thin films have (Orthorhombic) structure, the doping of all the elements in general caused to conform the crystalline nature and the preferred orientation at (002), with the gain in the crystalline size. The optical properties of the prepared films have been investigated. The optical absorption coefficient (a) of the films was determined from absorbance spectra in the range of wavelength (200-1100) nm. The optical energy gap was found to allow direct transition, which decreases with the doping process, also the optical constant have been calculated. The grain size and roughness have been measured with AFM, they increased by adding impurity element.