Structural Properties of GexSe1-x Thin Films Prepared by Semi-closed Space Technique

Abstract

Bulk and thin film Ge x Se 1-x alloys have been prepared with 0.1≤X≤0.5. The bulk materials were obtained by quenching from the melt. They have been used as source materials to produce thin film samples using the thermal evaporation method (semi-closed space technique). The composition of the obtained films was checked against the bulk ones by X-ray fluorescence (XRF) technique. X-ray diffraction patterns of the obtained compositions revealed the presence of some crystalline inclusions in the amorphous matrix for some compositions. Glass transition temperature measurements showed a maximum in the range X=0.25 to 0.32 where the glass forming ability is optimum. Measurements of the temperature dependence of the steady state dark current as a function of the Ge content has been recorded during heating and cooling cycles. A compensation effect has been found and characterized with two compensation temperatures, during the cooling cycle. Optical transmission, (UV) and infrared (IR), measurements have been performed. Energy band gap, width of the band tail and the refractive index have been calculated. Results have been interpreted in terms of the structural behavior of the samples under investigation in view of the models presented in literatures.