We report the first study of optical-emission properties associated with interface-state formation for metals on III-V semiconductor surfaces. Cathodoluminescence spectroscopy reveals discrete levels distributed over a wide energy range and localized at the microscopic interface. Our results demonstrate the influence of the metal, the semiconductor, and its surface morphology on the energy distributions. Evolution of spectral features with interface formation, particularly above monolayer metal coverage, is correlated with Fermi-level movements and Schottky-barrier heights.

• Received 24 April 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.487