An improved p-type semiconductor alloy film, an improved substantially intrinsic amorphous semiconductor alloy film, improved photovoltaic and photoresponsive devices incorporating such films and r.f. and microwave glow discharge methods for fabricating same. The improved semiconductor alloy films preferably include at least silicon deposited by the glow discharge of a compound containing at least silicon and a boron species that remains substantially monoatomic as it is incorporated into the silicon matrix. The p-type film is particularly stable, is characterized by a non-narrowed band gap, reduced bulk stress, improved morphology, growth and adhesion and reduced peeling and cracking. The substantially intrinsic film is characterized by substantially reduced Staebler-Wronski degradation. The method includes the novel step of introducing a boron species that does not form higher order boron hydrides or other boron polymers or oligomers in the glow discharge plasma.