last updated Saturday, April 3, 1999 2:36:30 AM.
© 1999 The Materials Research Society
M. Lisker, A. Krtschil, H. Witte, J. Christen
University of Magdeburg
D.J. As, B. Schottker, K. Lischka
University of Paderborn
This article was presented as part of Symposium G, "Gallium Nitride and Related Alloys" at the 1998 Fall Meeting of the Materials Research Society held in Boston, Massachusetts, November 30-December 4.
Nominally undoped cubic GaN epilayers deposited by rf-plasma assisted molecular beam epitaxy on semi-insulating GaAs substrates were investigated by electric and photoelectric spectroscopical methods. As a consequence of the existence of deep levels in the GaAs-substrate itself, special care has to be taken to separate the contributions of the substrate from that of the cubic GaN epilayer in the various spectra. Two different contact configurations (coplanar and sandwich structures) were successfully used to perform this separation. In the cubic GaN epilayer a trap with a thermal activation energy of (85±20)meV was found by thermal admittance spectroscopy and thermal stimulated currents. Optical admittance spectroscopy and photocurrent measurements furthermore revealed defects at EG-(0.04-0.13) eV, EG-(0.21-0.82) eV and two additional deeper defects at 1.91 eV and 2.1 eV, respectively. These defect related transitions are very similar to those observed in hexagonal GaN.
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Cite this article as: MRS Internet J. Nitride Semicond. Res. 4S1, G3.14 (1999).
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