Heterostructures on chalcogenide glass and their applications

Research conducted on electrical contact phenomena in chalcogenide glassy semiconductors (ChGS) took place simultaneously with advances in the electronic processes of these materials. The starting point for the research was the fac. that non-crystalline chalcogenides have a well-defined energy gap, E-g, determined values of electronic affinity χ and work function φ. As in crystalline materials, the space charge region (SCR) appears near the contacts. Parameters and properties of SCR depend on the contact materials, interface condition, and composition of ChGS. However, unlike crystalline semiconductors, ChGS exhibit a large density of localized states distributed quasi-continuously in the gap, yet the Fermi level is fixed near the middle of the gap independent of the magnitude of doping. These circumstances lead to low values of depletion length and other peculiarities of SCR. Therefore it is convenient to consider contact phenomena in ChGS for three basic types of structures: metal-glass, crystal-glass, and glass-glass.