Charge multiplication arising from carriers injected intop‐njunctions in gallium phosphide has been studied as a function of applied bias. From these and capacitance studies, the carrier ionization rate as a function of field has been determined. It is found to be very similar, both qualitatively and quantitatively, to the behavior in silicon. In particular, the mean free path for hot carriers between collisions involving optical phonon emission is of the order of 100 A. An additional result obtained from simple analysis of the photoresponse and capacitance behavior of the junctions is that the dominant carrier lifetime is 10−10sec.