Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 27: Nitrides: Preparation and characterization II

HL 27.11: Vortrag

Mittwoch, 14. März 2018, 12:15–12:30, EW 203

Effects of well width on the recombination dynamics in m-plane GaInN/GaN quantum wells — •Philipp Henning, Fedor Alexej Ketzer, Philipp Horenburg, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität Braunschweig

In this contribution we discuss the dependence of carrier recombination dynamics on quantum well width in nonpolar structures. For this purpose a set of m-plane GaInN/GaN quantum wells (QWs) with low indium content (≤ 10 %) and varying QW width (1...6 nm) is grown by MOVPE on GaN pseudo bulk substrates and measured by time-resolved photoluminescence spectroscopy. We find a single-exponential PL decay and large radiative recombination rates at low temperatures. The corresponding lifetimes of about 500 ps stay constant for all QW widths, which is expected for nonpolar structures due to the absence of internal polarization fields that would reduce the wave function overlap for wider wells. Furthermore, we discuss the behavior of the radiative recombination at elevated temperatures, where the increase in radiative lifetime varies with changing QW width. Additionally, a sharp drop in the nonradiative lifetime can be observed in the measurements, which is unexpected due to the low indium content and the high-quality substrates. The lifetimes at room-temperature are of the order of 100 ps or below, clearly showing the dominance of nonradiative recombination. Dislocations originating from the substrate and penetrating through the QW are relatively rare, indicating that defects form during the QW growth.