Optical properties of a high-quality insulating GaN epilayer
- Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States)
- Honeywell Technology Center, Plymouth, Minnesota 55441 (United States)
Picosecond time-resolved photoluminescence (PL) spectroscopy has been used to investigate the optical properties of an insulating GaN epilayer grown by metalorganic chemical vapor deposition on a sapphire substrate. Two emission lines at 3.503 and 3.512 eV in the continuous wave (cw) PL spectra observed at 10 K under a low excitation intensity ({approximately}23thinspW/cm{sup 2}) were identified as the band-to-band transitions involving the {ital A} and {ital B} valence bands, respectively. A third emission line at 3.491 eV was identified as a band-to-impurity transition involving a shallow donor. The PL decay behavior can be well understood with a model taking into account both the free carriers and impurities. The effective recombination lifetime of the band-to-band transition in GaN was found to be about 3.7 ns. Possible mechanisms for the band-to-band transition being dominant in this high quality insulating GaN epilayer have also been discussed. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 345407
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 25 Vol. 74; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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