ABSTRACT
This chapter discusses the basic properties of amorphous films deposited in a glow discharge. A glance at the programs of international conferences on amorphous semiconductors shows that amorphous silicon (a-Si:H) prepared by plasma decomposition of silane plays a dominant role in this field. The chapter focuses on those electronic properties of a-Si:H films which are regarded as relevant for the various technical applications of this material. A characteristic feature of amorphous semiconductors is the disorder-induced localization of states near the band edges, which leads to tails of localized states extending from the conduction and valence bands deep into the gap. These states are supposed to arise from potential variations due to fluctuations of the bond angle, dihedral angle, and bond length. Recombination processes in a-Si:H has been intensively studied, particularly by photoluminescence and photoconductivity. Various recombination models have been put forward to explain the temperature and intensity dependence of the photoconductivity.
