Document Type
Article
Original Publication Date
2010
Journal/Book/Conference Title
Journal of Applied Physics
Volume
107
Issue
11
DOI of Original Publication
10.1063/1.3430979
Date of Submission
October 2015
Abstract
Steady-state and transient surface photovoltage (SPV) in undoped GaN is studied in vacuum and air ambient at room temperature and 400 K with a Kelvin probe. The results are explained within a phenomenological model accounting for the accumulation of photogenerated holes at the surface, capture of free electrons from the bulk over the near-surface potential barrier, and emission of electrons from surface states into the bulk. Simple analytical expressions are obtained and compared with experimental results. In particular, the proposed model explains the logarithmic decay of the SPV after stopping illumination. Internal and external mechanisms of the SPV are discussed in detail. It is shown that an internal mechanism dominates at low illumination intensity and/or small photon energies, while external mechanisms such as charging of a surface oxide layer and photoinduced processes play a significant role for above-bandgap illumination with sufficient intensity.
Rights
Reshchikov, M. A., Foussekis, M., & Baski, A. A. Surface photovoltage in undoped n-type GaN. Journal of Applied Physics, 107, 113535 (2010). Copyright © 2010 American Institute of Physics.
Is Part Of
VCU Physics Publications
Comments
Originally published at http://dx.doi.org/10.1063/1.3430979