New alloys of hydogenated amorphous silicon with Al, Ga, S, and Se have been prepared by the rf glow discharge method. The energy gap of these materials can be varied in the 1–2 eV range, with the Al and Ga alloys being low band‐gap semiconductors, and the S and Se alloys having higher energy gaps. The light to dark conductivity ratios of the various systems have been measured. The best photoresponse (102–103) was obtained with the Se and S alloys.