Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 10: Nitrides

HL 10.3: Vortrag

Montag, 5. September 2022, 15:30–15:45, H34

Investigation of lateral charge carrier diffusion via micro-photoluminescence in InGaN MQWs and SQWs — •Conny Becht¹, Ulrich T. Schwarz¹, Michael Binder², Bastian Galler², Jürgen Off², Maximilian Tauer², Alvaro Gomez Iglesias², Heng Wang², and Martin Strassburg² — ¹Institute of Physics, Chemnitz University of Technology, 09126, Chemnitz, Germany — ²ams-OSRAM International GmbH, Leibnizstr. 4, 93053 Regensburg, Germany

InGaN multi-quantum well (MQW) structures are used to obtain highly efficient blue light emitting diodes (LED). After the injection of carriers into the active layer of blue LEDs, a part of the carriers diffuses laterally before recombining (non-)radiatively. The diffusion behaviour in InGaN MQWs is up to now poorly understood.

In this study InGaN MQWs and single QWs (SQW) are investigated by micro-photoluminescence at room temperature. To study the diffusion behaviour, the excitation spot is decoupled from the detection area, which we call a pinhole scan. With the size of the excitation spot known, conclusions about the diffusion length of the charge carriers after optical pumping can be drawn. For deeper analysis of the diffusion behaviour the excitation density is varied and an external bias can be applied in addition.

The results show a long-range diffusion up to several 10 µm’s. The energy shows a increasing blue shift with higher excitation power at the center (i.e. excitation spot).