Optical properties of GaN pyramids
- Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States)
- Honeywell Technology Center, 12001 State Highway 55, Plymouth, Minnesota 55441 (United States)
Picosecond time-resolved photoluminescence (PL) spectroscopy has been used to investigate the optical properties of GaN pyramids overgrown on hexagonal-patterned GaN(0001) epilayers on sapphire and silicon substrates with AlN buffer layers. We found that: (i) the release of the biaxial compressive strain in GaN pyramids on GaN/AlN/sapphire substrate led to a 7 meV redshift of the spectral peak position with respect to the strained GaN epilayer grown under identical conditions; (ii) in the GaN pyramids on GaN/AlN/sapphire substrate, strong band edge transitions with much narrower linewidths than those in the GaN epilayer have been observed, indicating the improved crystalline quality of the overgrown pyramids; (iii) PL spectra taken from different parts of the pyramids revealed that the top of the pyramid had the highest crystalline quality; and (iv) the presence of strong band-to-impurity transitions in the pyramids were primarily due to the incorporation of the oxygen and silicon impurities from the SiO{sub 2} mask. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 321453
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 9 Vol. 74; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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