Time-Resolved Photoluminescence in Strained GaN Layers

✍ Scribed by Pozina, G. ;Edwards, N.V. ;Bergman, J.P. ;Monemar, B. ;Bremser, M.D. ;Davis, R.F.

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 95 KB
• Volume: 183
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/1521-396x(200101)183:1<151::aid-pssa151>3.0.co;2-c

✦ Synopsis

A set of GaN epilayers grown by metalorganic chemical vapor deposition on 6H-SiC substrates was studied by time-resolved photoluminescence (PL) spectroscopy. The PL spectra are dominated by the free A exciton (FE A ) and by the neutral-donor-bound exciton (D 0 X) transitions. The position of FE A indicates that the GaN layers are under tension. We observe that the recombination lifetime for the FE A is about 40-50 ps in all the layers, whereas the recombination time for the D 0 X varies for different samples. We found that the recombination lifetimes for D 0 X have a clear dependence on the position of FE A ; i.e. the recombination lifetime increases with decreasing strain in the layers. The results can be explained in terms of the character of the hole states involved in the donor-bound exciton recombination.