Nitride-based MSM UV photodetectors with photo-chemical annealing Schottky contacts

• DOI: 10.1016/j.sse.2004.11.017
• Publication Date: 2005-01-25T18:14:04Z
• Authors: Y.K. Su; P.C. Chang; C.H. Chen; S.J. Chang; C.L. Yu; C.T. Lee; H.Y. Lee; J. Gong; P.C. Chen; C.H. Wang
• Keywords: Photocurrent; Photoconductivity; Ultraviolet

Abstract The undoped GaN (u-GaN) and two-dimensional electron gas (2DEG) metal–semiconductor–metal (MSM) photodetectors with semi-transparent Ni/Au Schottky barrier contact electrodes were fabricated. It was found that we could achieve a larger Ni/Au transmittance, higher Schottky barrier heights and larger photocurrent to dark current contrast ratios by photo-chemical annealing of these photodetectors in O 2 . It was also found that the maximum quantum efficiencies were 13% and 57% for the photo-chemical annealing u-GaN and 2DEG photodetectors, respectively. Furthermore, it was found that we could achieve a larger responsivity, a lower noise level and a larger detectivity by using the 2DEG structure.