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Electrical and optical properties of bulk GaN substrates studied by Kelvin probe and photoluminescence.

Authors :
McNamara, J. D.
Foussekis, M. A.
Baski, A. A.
Li, X.
Avrutin, V.
MorkoƧ, H.
Leach, J. H.
Paskova, T.
Udwary, K.
Preble, E.
Reshchikov, M. A.
Source :
Physica Status Solidi (C); Mar2013, Vol. 10 Issue 3, p536-539, 4p
Publication Year :
2013

Abstract

We have investigated the N- and Ga-polar faces of bulk GaN substrates with photoluminescence (PL) and the surface photovoltage (SPV) technique using a Kelvin probe attached to an optical cryostat. Experiments were conducted in vacuum. Some of the surfaces were mechanically polished (MP), while others were epi-ready after a chemical-mechanical polish (CMP). From the SPV measurements, the band bending in a sample having both surfaces treated with the CMP method was calculated to be about 0.83 and 0.70 eV for the Ga- and N-polar surfaces, respectively. The restoration of the SPV after ceasing the UV illumination showed that the SPV from CMP-treated surfaces behaved as predicted by a thermionic model, whereas the SPV from MP-treated surfaces restored with a much faster-than-predicted rate. This result can be interpreted by the hopping of charge carriers in the highly-defective near-surface layer of the MP-treated samples. Remarkably, removing the top 700 nm defective layer by dry etching restored the quality of the electrical and optical properties of GaN. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
18626351
Volume :
10
Issue :
3
Database :
Complementary Index
Journal :
Physica Status Solidi (C)
Publication Type :
Academic Journal
Accession number :
85974307
Full Text :
https://doi.org/10.1002/pssc.201200662