Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 21: Quantum Dots and Wires, Optical Properties I: Nitrides

HL 21.4: Vortrag

Dienstag, 23. März 2010, 10:15–10:30, H17

Electroluminescence from an isolated single InGaN QD up to 150 K in the green spectral region — •Joachim Kalden, Christian Tessarek, Kathrin Sebald, Stephan Figge, Carsten Kruse, Detlef Hommel, and Jürgen Gutowski — Institute of Solid State Physics, University of Bremen, P.O. Box 330 440, D-28334 Bremen, Germany

Semiconductor quantum dots (QDs) are known to be favourable for solid state single photon sources. As state-of-the-art detectors have their efficiency maximum in the green spectral region, InGaN QDs are particularly suitable to realize such devices, providing emission in the visible spectral range. However, only few reports exist on the electroluminescence (EL) of nitride QDs. We present EL from a p-i-n diode containing InGaN QDs as active layer. The onset bias is 3.15 V at room temperature (RT), which is raised to 8.8 V at 4 K mainly due to carrier freeze-out effects. The intensity at RT remains at 28% of the intensity at 4 K. Further, slope variation or shift of the ensemble EL are shown to be negligible at RT for driving currents from 10 mA to 150 mA. This demonstrates the excellent stability of the EL. At 4 K and for a constant driving current of 19 mA, sharp emission lines are detectable nearly background-free at the lower energy tail of the emission band. EL from an isolated single InGaN QD emitting at 527 nm is obtained from 4 – 90 K. From 100 K onwards, the distinct QD emission is still visible may be traced up to 150 K as a shoulder on a raising background. These results hold much promise for future electrically driven single photon emission at room temperature.