Photorefractive determination of the sign of photocarriers in InP and GaAs.

Measurements of the photorefractive behavior of many ferroelectric and piezoelectric insulators have yielded valuable information concerning the nature of deep levels and photocarrier transport, by optical techniques alone. It has not been recognized until recently, however, that semiconductors of current technological interest such as InP, GaAs and CdTe, which have the zinc blende structure, also exhibit photorefractive behavior, and that the same technique developed for insulators can be advantageously applied to studies of the material properties of these semiconductors.