AbstractSynchrotron radiation-based x-ray photoemission spectroscopy was used to study the Fermi level position within the band gap for thin metal overlayers of Au, Ni, and Ti on n-GaN and p-GaN. The Fermi level position was determined with the measured Fermi edge of the metal on the sample in order to correct for the presence of non-equilibrium effects. There are two different behaviors observed for the three metals studied. For Au and Ti, the surface Fermi positions on n-GaN and p-GaN are roughly 0.5 eV apart within the band gap. For Ni, the n-GaN and p-GaN have a Schottky barrier that forms at the same place at the gap.
Photoellipsometry determination of surface Fermi level in GaAs (100)