Doping in metal chalcogenide glasses

Chalcogenide glasses that contain sufficient concentrations of metal atoms can be p-type doped. This doping results in part because the local structural order is tetrahedral at the metal and the chalcogen sites in these glasses. At concentrations exceeding 1019 cm−3, oxygen promotes doping by increasing the densities of dangling-bond defects at threefold-coordinated chalcogens, which are the doping sites in these glasses. For oxygen concentrations below 1019 cm−3, the conductivity is independent of oxygen, and therefore is controlled by other mechanisms. The compositions Cu6As4S9 and Cu6As4Se9 are studied, because at these compositions the S (or Se) and Cu atoms are all tetrahedrally coordinated and there exist only Cu-S and As-S (or Cu-Se and As-Se) bonds.