Electronic Processes at the GaN Surface

The electronic charge transfer processes across the GaN surface have been investigated in this work by combining conductance and contact potential measurements. ln particular, we have probed the role of localized shallow defect states in the kinetics of photo-generated charges. We found that these states are responsible for the trapping of photo-generated electrons in the space charge region close to the surface, which explains the slow response of the PC to illumination. We also evaluated the influence of electrically active surface states on the charge transfer across the GaN/electrolyte interface.