Study of near-threshold gain mechanisms in MOCVD-grown GaN epilayers and InGaN/GaN heterostructures
The authors report the results of an experimental study on near-threshold gain mechanisms in optically pumped GAN epilayers and InGaN/GaN heterostructures at temperatures as high as 700 K. They show that the dominant near-threshold gain mechanism in GaN epilayers is inelastic exciton-exciton scattering for temperatures below {approximately} 150 K, characterized by band-filling phenomena and a relatively low stimulated emission (SE) threshold. An analysis of both the temperature dependence of the SE threshold and the relative shift between stimulated and band-edge related emission indicates electron-hole plasma is the dominant gain mechanism for temperatures exceeding 150 K. The dominant mechanism for SE in InGaN epilayers and InGaN/GaN multiple quantum wells was found to be the recombination of carriers localized at potential fluctuations resulting from nonuniform indium incorporation. The SE spectra from InGaN epilayers and multiple quantum wells were comprised of extremely narrow emission lines and no spectral broadening of the lines was observed as the temperature was raised from 10 K to over 550 K. Based on the presented results, they suggest a method for significantly reducing the carrier densities needed to achieve population inversion in GaN, allowing for the development of GaN-active-medium laser diodes.
- Research Organization:
- Oklahoma State Univ., Stillwater, OK (US)
- Sponsoring Organization:
- US Department of the Navy, Office of Naval Research (ONR); Defense Advanced Research Project Agency; US Department of the Air Force; National Science Foundation (NSF)
- OSTI ID:
- 20104746
- Resource Relation:
- Conference: 1999 Materials Research Society Spring Meeting, San Francisco, CA (US), 04/05/1999--04/08/1999; Other Information: PBD: 1999; Related Information: In: Wide-band semiconductors for high-power, high-frequency and high-temperature applications -- 1999. Materials Research Society symposium proceedings: Volume 572, by Binari, S.C.; Burk, A.A.; Melloch, M.R.; Nguyen, C. [eds.], 575 pages.
- Country of Publication:
- United States
- Language:
- English
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