Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 15: III-V semiconductors II
HL 15.6: Vortrag
Dienstag, 28. März 2006, 12:15–12:30, POT 51
The influence of defects on the recomination dynamics in InGaN quantum wells grown on sapphire and GaN substrates — •T. Stempel Pereira1, M. Dworzak1, A Hoffmann1, G. Franssen2, T. Suski2, S. Grzanka2, R. Czernecki2, M. Leszczynski2, and I. Grzegory2 — 1Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2Institut of High Pressure Physics ’Unipress’, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw, Poland
We studied the influence of localization and defects on the recombination in single InGaN quantum wells on sapphire- and GaN-substrates, respectively. Time-integrated and time-resolved PL measurements were performed. Temperature dependent radiative and non-radiative lifetimes and the depth of the localization potentials could be determined. It appears on both substrates, that due to the high density of defects, localization is a crucial condition for radiative recombination. When carriers leave their localization potential due to thermal activation, they recombine non-radiatively at defects.
Intensity dependent time-resolved PL measurements cast new light on the significance of defects. At 10 K we observe an increasing influence of non-radiative recombination via defects with growing excitation intensity due to the filling of the localized states. However, at room temperature the decay decelerates with increasing excitation intensity. This decreasing significance of the defects can be explained with a saturation of defect states.