Raman scattering studies of surface space charge layers and Schottky barrier formation in InP

We show that Raman scattering by LO phonons and their coupled modes can be used to obtain quantitative information on the band bending at surfaces or interfaces of doped III–V semiconductors. We have studied Schottky barrier formation and effects related to surface photovoltage at etched <111≳B surfaces of InP. These experiments yield information similar to that obtained from photoemission and photovoltage measurements, but they can also be carried out on surfaces which are contaminated or even covered with partially transparent layers such as metallic films.