Absolute conduction- and valence-band positions for Ge from an anisotropic model of photoemission

An anisotropic direct-transition model for single-crystal semiconductors is shown to predict the direct-transition features seen in experimental photoemission spectra for Ge(111) for hν20 eV. By comparing theory with experiment, all the conduction and valence bands at L and X within 1 Ry of the gap are determined. Comparison of experiment with current band models suggests that an ∼ 10% self-energy correction may be needed to describe high-energy optical transitions. © 1974 The American Physical Society.