Core level photoemission study of the deposition of thin iron layers on sulphur terminated InP(100) surfaces

Abstract

The deposition of thin layers of iron on sulphur terminated InP(100) surfaces has been investigated by soft X-ray core level photoemission. The sulphur treatment was carried out in situ using an ultrahigh vacuum compatible electrochemical source. Thin iron layers were deposited onto the sulphur induced (2×1) surface reconstruction of both n- and p-type InP(100) at room temperature. The Fermi level position for both doping types following sulphur deposition and anneal was found to lie in the range 0.9–1.2 eV above the valence band maximum. There is evidence of a strong chemical interaction between iron and the sulphur terminated surface which removes the (2×1) surface reconstruction and moves the Fermi level back towards a mid gap position for both doping types. Chemically shifted components of the In4d, P2p and S2p core levels diffuse out through the growing metal overlayer producing a mixed chemical phase interfacial region which, for the metal coverages investigated, produced no evidence of heteroepitaxial growth.