Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 59: Nitrides: Preparation and Characterization II

HL 59.3: Vortrag

Mittwoch, 22. März 2017, 15:15–15:30, POT 251

Interplay between yellow and blue luminescence bands in GaN:C — •Zahid Usman, Martin Feneberg, Andreas Lesnik, Marc P. Hoffmann, Armin Dadgar, and Rüdiger Goldhahn — Otto-von-Guericke Universität Magdeburg, Institut für Experimentelle Physik

Carbon doped GaN has attracted much attention due to its compensating nature for unintentionally introduced background electron densities. That is why a semi-insulating buffer layer of this material is often introduced in high electron mobility transistors. Photoluminescence can be a useful tool to understand the charge states of deep defects which yield different recombination channels in GaN. Here, we present photoluminescence spectra with different excitation densities, recorded on carbon and silicon co-doped GaN samples. Depending on dopant densities, the photoluminescence spectra show yellow and blue luminescence bands with different intensity ratios. For increasing pump power density the yellow luminescence band saturates at a critical excitation power density while the blue luminescence band increases further. Our results suggest that both recombination bands evolve from the deep carbon acceptor in different charge states. The yellow band is assigned to come from carbon in (-/0) state while the blue band originates from carbon in (0/+) charge state.