Electronic properties of some simple chalcogenide glasses

The dc and ac conductivity, thermoelectric power, optical absorption and carrier mobility of As₂S₃, As₂Se₃ and some other chalcogenide glasses are described and discussed. The question of band or hopping conduction is considered and it is concluded that although the ac conductivity involves hopping, the dc properties are best viewed in terms of a band model with a "mobility gap" as introduced by Mott and Cohen. There are, however, some unresolved problems, particularly relating to the ac conductivity.