Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 50: Nitrides: Preparation and Characterization

HL 50.6: Talk

Wednesday, March 22, 2017, 11:30–11:45, POT 251

Impact of strain and valence band structure on radiative and non-radiative recombination in m-plane GaInN/GaN quantum wells — •Philipp Henning, Torsten Langer, Manuela Klisch, Fedor Alexej Ketzer, Philipp Horenburg, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität Braunschweig

Even for thin c-plane quantum wells (QWs), where the polarization field is negligible, we observe longer room-temperature radiative lifetimes compared to m-plane structures. We use time-resolved photoluminescence spectroscopy to measure the radiative and non-radiative carrier lifetimes in GaInN/GaN QW structures grown by MOVPE, where we find room-temperature radiative lifetimes between 1ns and 200ps for m-plane QWs and minimum values around 2ns for c-plane structures. The difference amounts up to one order of magnitude and can partly be explained by an increased exciton binding energy for non-polar QWs. As confirmed by simulations, another major contribution to the shorter radiative lifetimes stems from a modified valence band structure, which results in reduced effective hole masses for non-polar QWs. A change of the strain state in the QW, as it is present for higher indium contents, has further impact on the valence band structure. By introducing a metamorphic AlInN buffer layer we aim to reduce the strain in the QW, which allows for a more detailed study of the impact of the valence band structure on the radiative lifetimes. Moreover, we find increasing non-radiative lifetimes as a consequence of the reduced strain state and lower defect formation in the QW.