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Application of picosecond four-wave mixing and photoluminescence techniques for investigation of carrier dynamics in bulk crystals and heterostructures of GaN
|Kestutis Jarasiunas 1, T. Malinauskas 1, Arunas Kadys 1, M. Sudzius 1, R. Aleksiejunas 1, Saulius Miasojedovas 1, Saulius Jursenas 1, A. Zukauskas 1, Daniela Gogova 2, A. Kakanakova-Georgieva 2, E. Janzen 2, H. Larsson 2, Bo Monemar 2, P. Gibart 3, B. Beaumont 3|
1. Vilnius University, Institute of Materials Science and Applied Research (IMSAR, VU), Sauletekio 9, building III, Vilnius LT-2040, Lithuania
We studied defect-density governed photoelectric parameters in GaN heterostructures and bulk crystals by using the time-resolved techniques of picosecond four-wave mixing (FWM) and photoluminescence (PL). A few mm-thick GaN layers were grown on 6H-SiC or 4H-SiC substrates by hot-wall MOCVD with varied growth parameters, while the 270-mm-thick free-standing bulk crystal was grown by HVPE on a two-step epitaxial lateral overgrown GaN template on sapphire. FWM was realized by recording transient free carrier gratings at interband excitation at 355 nm wavelength and probing their kinetics by the delayed probe beam at 1064 nm. For spectrally and temporally resolved PL, the samples were excited at 266 nm and luminescence was measured in backward geometry. The excitation density varied up to a few mJ/cm2, what allowed us to study effects at nonequilibrium carrier density from 1018 up to 5x1019 cm-3.
Presentation: oral at E-MRS Fall Meeting 2004, Symposium C, by Kestutis Jarasiunas
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-04-28 13:52 Revised: 2009-06-08 12:55