4 March 2013 Recombination dynamics in non-polar m-plane GaN investigated by time- and polarization-resolved photoluminescence
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Abstract
The carrier recombination dynamics in bulk m-plane GaN were investigated by excitation and temperature dependent time-resolved photoluminescence (TRPL) spectroscopy. Polarization-resolved measurements of photoluminescence (PRPL) spectra were performed to evaluate the individual contributions of excitons and free carriers to the radiative recombination. The polarization degree and PL lifetime were strongly correlated and dependent on the populations of free carriers and excitons at different excitation density and temperature levels. The free carrier concentration was found to increase due to the dissociation of excitons at high excitation density and temperatures. The excitonic PL life time was found to be ~ 0.7 ns at 10 K at the lowest excitation density used 0.04 μJ/cm2, where no exciton screening was present as confirmed by the 100% polarization degree. The polarization degree obtained at different excitation levels and temperatures by comparing the PL decay times to the excitonic PL lifetime correlated very well with the polarization degree obtained from the excitation dependent PRPL measurements. Finally, it was shown that TRPL and PRPL can be used to separate the excitonic and free carrier contributions to the recombination dynamics in m-plane GaN at any temperature and excitation density.
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Serdal Okur, Kestutis Jarašiūnas, Shopan din Ahmad Hafiz, Jacob Leach, Tania Paskova, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür, "Recombination dynamics in non-polar m-plane GaN investigated by time- and polarization-resolved photoluminescence", Proc. SPIE 8625, Gallium Nitride Materials and Devices VIII, 86252D (4 March 2013); doi: 10.1117/12.2005252; https://doi.org/10.1117/12.2005252
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