Surface core-level binding-energy shifts for the cleaved GaP(110) surface

Ga 3d and P 2p core-level photoemission spectra have been collected from cleaved GaP(110) surfaces and surface core-level binding-energy shifts of -0.41 and +0.31 eV have been obtained for the P 2p and Ga 3d core levels, respectively. The energy dependence of the P 2p core-level line shape has also been studied and estimates of the photoelectron escape depth in GaP are made for photoelectrons with kinetic energies in the range 10--60 eV.