INVERSE-PHOTOEMISSION STUDY OF NON-RECONSTRUCTED SI(111) SURFACES - A COMPARISON BETWEEN H-SI(111)1X1 AND AS-SI(111)1X1

The lower conduction-band states of Si(111) have been measured by k(parallel to)-resolved inverse photoelectron spectroscopy (KRIPES) on non-reconstructed surfaces obtained either by saturating the dangling bonds with atomic hydrogen or by replacing the Si surface atoms with As atoms. On the H-Si(111)1 x 1 surface, two conduction bands are measured whose asymmetry in the Gamma-($) over bar M direction reveals their bulk character. The same conduction band states are also measured on the As:Si(111)1 x 1 surface, however at lower energies as a result of the higher electronegativity of the As atoms. These latter data are in excellent agreement with recent calculations using the quasi-particle formalism.