PROPER INTERPRETATION OF PHOTOCONDUCTIVE DECAY TRANSIENTS IN SEMICONDUCTORS HAVING FINITE SURFACE RECOMBINATION VELOCITY

The influence of finite surface recombination velocity on the proper i nterpretation of photoconductive decay (PCD) transients in semiconduct ors is discussed. The limitations of simple analytical equations which relate the observed effective lifetime to the material parameters are considered. It is shown that, under most circumstances, the correct a pplication of the appropriate analytical expression requires some prio r knowledge of the material parameters under investigation. several me thods are proposed to extract useful information from PCD experiments. Finally, the practicality of these methods is investigated by measuri ng the effective lifetimes of high-purity germanium and float-zone sil icon using a noncontact PCD technique.