Electronic Transport in Hydrogenated Amorphous Silicon

Abstract

ABSTRACTThe puzzles regarding the magnitude of the free electron mobility in hydrogenated amorphous silicon are examined. It is suggested that highlevel double injection produces a metastable increase in the carrier mobility by neutralizing positively and negatively charged defect states thereby eliminating long-range potential fluctuations. Since these defect states cannot be neutralized under low-level or single injection, they both contribute to the modulation of the conduction band and increase the freecarrier scattering. If the latter is the predominant scattering mechanism, the neutralization of charged defects directly leads to a mobility increase under double-injection conditions. We discuss the various implications of this model, and present recent experimental results in agreement with these ideas.