Many-body effect at metal-semiconductor junctions. II. The self energy and band structure distortion

For pt. I see abstr. A75119 of 1972. When a metal is placed upon the surface of a semiconductor the resulting changes in the electron interaction near the interface produce changes in the exchange and correlation potential. The most important aspect is that the potential changes differ with the state considered. In particular the reaction of the valence and conduction bands are very different causing changes in the band gap in the surface region. The image potential has opposite signs in the valence and conduction band corresponding to the semiclassical electron and hole picture; this is shown to be due to the screened exchange difference between the two bands. The screened exchange difference between the two bands is calculated numerically up to the surface for the two limiting cases of a covalent and ionic semiconductor. Finally the difference in behaviour of these two types is briefly discussed in the light of the results on Schottky barriers.