The effect of hydrogen dilution of the gas plasma on glow discharge a-Ge:H

A series of films of amorphous hydrogenated germanium has been produced using the r.f. glow discharge technique by varying the H2/GeH4 ratio in the gas plasma from 0 to 50 while keeping all other deposition parameters constant. Electronic, optical, and structural characterization has been performed. No significant changes in optical and electronic properties were observed for this range of dilution, in contrast to repeated reports on the hydrogenated silicon-germanium alloy system. However, small systematic changes in structure are observed using TEM techniques. The authors conclude that the observed differences are unimportant in determining the optical and electronic properties of this material