Nongeminate Recombination ofa-Si: H

The nongeminate recombination of photogenerated holes in undoped $a$-Si: H has been studied by the delayed-collection-field technique. The analysis of experimental data indicates that the bulk and surface losses of holes involve extremely slow processes with temperature dependences similar to that of their drift mobility. The results indicate that the recombination lifetime is remarkably long (>10 msec) at room temperature. When the same analysis is applied to the photoinduced absorption data of Vardeny et al., the carrier involved can be identified as the electron, and a similar conclusion regarding carrier loss is reached.