Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Nitrides: Preparation and characterization I

HL 24.11: Vortrag

Mittwoch, 3. April 2019, 12:15–12:30, H31

Thermal activation of non-radiative recombination processes in III-nitride quantum wells — •Philipp Henning, Torsten Langer, Fedor Alexej Ketzer, Silvia Müllner, Philipp Horenburg, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik & Laboratory for Emerging Nanometrology, Technische Universität Braunschweig, 38106 Braunschweig, Germany

In order to understand the origins of defect-related non-radiative charge carrier losses in III-nitride quantum wells, the thermal activation of non-radiative charge carrier recombination is analyzed. Therefore, time-resolved photoluminescence measurements are performed in a wide temperature range between 3.5 and 500 K, which allows a more accurate determination of activation energies compared to an analysis limited to room temperature. Among the possible non-radiative mechanisms are thermal activation over potential barriers, exciton dissociation and multi-phonon capture, which may also be present at low temperatures via tunneling-assisted processes. We compare quantum well samples with different crystal orientations and substrate qualities, as well as the impact of intentionally introduced defects by ion implantation, in order to distinguish the thermal activation of different non-radiative recombination mechanisms. The measurements show activation energies of 5 to 50 meV, reaching up to hundreds of meV. At room temperature, a broad range of non-radiative lifetimes between <100 ps and several 10 ns is found, depending on the crystal orientation and the defect density controlled by the implantation dose.