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HL: Fachverband Halbleiterphysik

HL 27: GaN: preparation and characterization I

HL 27.2: Talk

Wednesday, March 25, 2009, 09:45–10:00, BEY 81

Time-resolved measurements on blinking dots in InGaN/GaN quantum wells — •Anne Kuhnert¹, Clemens Vierheilig¹, Tobias Meyer², and Ulrich T. Schwarz¹ — ¹Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany — ²OSRAM Opto Semiconductors GmbH, Leibnizstraße 4, 93055 Regensburg, Germany

In some InGaN/GaN quantum well samples the quantum well photoluminescence under cw laser excitation is not homogenously distributed, but shows dots with different emission wavelengths. The colors of the dots vary from red over green to blue. Some of these dots show a switching behavior between two intensity levels. The timescale of the blinking phenomenon is of the order of 10⁻² s up to some seconds. At low excitation densities the time slices of on-state and off-state are mainly the same. With increasing excitation density the percentage of the off-state decreases and at high excitation intensities the dots stay permanently on. The photoluminescence of these samples is measured with a confocal microscope with high spatial resolution. The signal is detected time resolved by a photomultiplier tube.