Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 5: Nitrides: mostly transport properties and recombination processes
HL 5.2: Vortrag
Montag, 31. März 2014, 09:45–10:00, POT 251
Recombination rates in GaInN/GaN quantum wells: Beyond the ABC model — •Torsten Langer1, Alexey Chernikov2, Dimitri Kalincev2, Marina Gerhard2, Heiko Bremers1, Uwe Rossow1, Martin Koch2, and Andreas Hangleiter1 — 1Institute of Applied Physics, Technische Universität Braunschweig — 2Faculty of Physics and Materials Science Center, Philipps-Universität Marburg
We report on an excitonic enhancement of recombination processes in GaInN/GaN single quantum wells being evident from temperature and density dependent time-resolved photoluminescence spectroscopy over a wide range of excitation densities. The proposed method allows for a determination of the radiative and nonradiative recombination times as a function of the excess carrier density (rather than a function of the generation rate) free of any a priori assumptions on the dynamics of the recombination processes. Excitonic radiative recombination is evidenced by density independent radiative lifetimes in the high injection regime, i.e. excess densities are larger than the background density. The transition from low to high injection is calibrated via the observed increase of Shockley-Read-Hall lifetimes in the intermediate regime. At high densities, a weak temperature dependence of nonradiative lifetimes that are proportional to the inverse of the density imply an excitonic, threshold-less Auger process. The density dependence of both radiative and nonradiative lifetimes thus differs strongly from the predictions of simple free-carrier ABC models.