Structure and optical properties of chalcogenide glassy semiconductors of the As–Ge–Se system

The types of structural elements and chemical bonds forming an amorphous matrix of chalcogenide glassy semiconductors of the As–Ge–Se system and changes occurring in them depending on the chemical composition are determined using a method for studying the Raman and transmission spectra and density measurements. It is shown that a transition from the elastic to isostatic state and then to the stressed-rigid state occurs in the system under study with increasing arsenic and germanium contents. The observed changes in the Raman spectra and the features of the dependences of optical and other parameters on the chemical composition are explained within the chemical-ordering model, taking into account the existence of local states near the allowed band boundaries.