Photoconductivity of amorphous GexAsxSe1-2x and (As4S3Se3)1-xSnx thin films

Arsenic selenide glasses are well known as high photosensitive materials with a wide range of application in optoelectronics and information storage systems. Besides, it was found that the impurities influence the electrical and photoelectrical characteristics of the amorphous material, due to the changes in the density of localized states. Introduction of the elements of IV group of periodic table in selenide and sulphide glasses, such as Sn and Ge, conduct to the appearance of tetrahedral structural units in the base glass, which change the coordination number. These particularities lead on non-monotonous dependence of physical properties on the glass composition. Besides that, recently it was established, that in the disordered network of glassy system Ge x As x Se 1-2x exists three distinct phases, floppy, intermediate and stressed rigid, and the dependence of physical properties of the average coordination number Z. In the present paper the experimental results on steady-state photoconductivity of amorphous Ge x As x Se 1-2x and (As 4 S 3 Se 3 ) 1-x Sn x thin films are presented and discusses. It was shown, that the spectral distribution of the stationary photoconductivity for both glass systems depends on the composition and polarity on the illuminated electrode. The experimental results are discussed in terms of multiple trapping model for amorphous materials, with exponential distribution of localized states in the band gap.