Transport and electrically detected electron spin resonance of microcrystalline silicon before and after electron irradiation

We have applied electro-optical techniques and electrically detected magnetic resonance to investigate microcrystalline silicon before and after irradiation with 1-MeV electrons. Irradiation with electrons induces pronounced changes in the optical and electronic properties, namely, an increase in subgap absorption as measured by the constant photocurrent method and a deterioration of the dark and photoconductive properties. Electrically detected magnetic resonance (EDMR) measured in the photocurrent mode shows an increased dangling-bond contribution and a change in the recombination path with sample irradiation. This is also reflected in the temperature-dependent Rose factor. Below 50 K we find an EDMR signal that we attribute to the recombination of conduction electrons in shallow traps with dangling bonds. We also find an 'enhancement' EDMR signal in the dark current with a typical g value for dangling bonds and which is almost unaffected by electron irradiation