Determining band offsets using surface photovoltage spectroscopy: The InP/In0.53Ga0.47 heterojunction

A direct technique for determining band offsets at semiconductor heterojunctions is presented, which is applicable to at least any type I heterojunction, where the top layer doping is sufficiently low. The technique is based on surface photovoltage spectroscopy measurements as a function of overlayer thickness, A numerically simulated example shows that the band offset is a very strong function of the critical overlayer thickness, at which the overlayer contribution to the surface photovoltage spectrum appears, The method is applied to the technologically important InP/InGaAs heterojunction and is shown to yield the commonly accepted band offset value. (C) 1996 American Institute of Physics.