Picosecond Photoconductivity in Amorphous Silicon

Abstract

In amorphous semiconductors, states lie in bands separated by energy gaps, as in the crystalline case. In an effort to explain some of the differences between the amorphous and crystalline states, Anderson [1] has proposed that the spatial randomness of the atomic potential, due to the intrinsic disorder of the lattice, gives rise to states localized to within a few lattice sites - localized states. The high-mobility valence and conduction-band states are called extended states. There is also extrinsic disorder within the lattice due to the presence of structural defects (divancies, microvoids, etc.), which depend heavily upon the method of preparation of the amorphous semiconductor. The question of electrical transport in amorphous semiconductors has evoked a vast compendium of new physics and many unresolved questions [2]. For example, there is the question of the relative importance of the various modes of electronic conduction such as extended state transport, hopping between localized states in a continuous random network, hopping between isolated defect sites, and small polaron motion [2].KeywordsElectron Spin ResonanceAmorphous SiliconAmorphous SemiconductorDrift MobilityIntrinsic DisorderThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.