Electronic properties of the InP(100) surface

We report a first investigation of the structural and electronic properties of InP(100). Through an adequate preparation, a clean surface with a (4 × 2) reconstruction is obtained. UPS and ELS studies of this surface, with in-situ reference to the (110) cleaved surface, reveal large densities of gap surface states, both near the conduction and the valence bands. A small density of mid-gap surface states strongly pins the Fermi level. Measurements of the surface recombination velocity by photoluminescence show that they also act as surface traps. It is concluded that the InP(100) surface is very similar to perturbed (110) surfaces and is rough on a microscopic scale.