Inverse Photoemission and Kelvin Probe Studies of the Au/GaP(110) Interface

We performed angle-integrated inverse-photoemission experiments on the Au/GaP(110) interface in the low-coverage regime. For a gold deposition of 0.5 Angstrom we found the IPES spectrum shifting by 0.25 eV towards lower energies below the Fermi reference level. This result is attributed to an excess of positive accumulated charge at the interface induced by the impinging electrons. This shift is consistent with our calculations based on the thermionic field emission model for transport processes in the Schottky barrier. Contact potential difference measurements under different illumination conditions were used to correlate the above electron induced voltage and the photovoltage observed on the same sample.