Surface effects in n-type InSb photoconductors

Results of field experiments performed with InSb indicate that the lifetime is shortened when the surfaces are inverted. Experiments were performed with a transparent field plate on top of a passivation layer. In inversion, measured photoconductive lifetimes decrease; this indicates that surface recombination is occurring. In accumulation, the lifetimes become independent of applied potential; this indicates that bulk recombination is occurring. The bulk dominated photoconductive lifetime is believed to be caused by Shockley-Read recombination mechanisms. At low temperatures (less than 100 K) traps become activated, and experiments indicate that the traps are located at the surface.