Substitutional doping of amorphous silicon a comparison of different doping mechanisms

The doping mechanism in a‒Si: H has been investigated through a series of model calculations. Two different mechanisms have been considered: (i) the dangling-bond concentration near midgap, N d∼1017cm-3, and the doping efficiency, η = 1, are relatively high and independent of the dopant concentration, and (ii) N d and η vary according to Street's auto-compensation reactions. The experimental conductivity data could be fitted only with this latter model. Further considerations have revealed that the auto-compensation model can satisfactorily account for a large body of experimental data.