Picosecond-laser-excited photoluminescence study of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire under selective and non-selective excitation conditions
S. Tanaka1, R. Ishii1, N. Susilo2, T. Wernicke2, M. Kneissl2,3, M. Funato1, and Y. Kawakami1
Published in:
Jpn. J. Appl. Phys., vol. 61, no. 11, pp. 112002 (2022).
Abstract:
The radiative recombination efficiency (RRE) of AlGaN quantum wells on epitaxially laterally overgrown AlN/sapphire templates was investigated by picosecond-laser–excited photoluminescence (PL) spectroscopy under selective and non-selective excitation conditions. The PL efficiency, which was deduced by excitation-power-dependent PL measurements at low temperature (LT) and room temperature (RT), was unity at LT under both excitation conditions; However, at RT, the PL efficiency under non-selective excitation conditions was lower than that under selective excitation conditions. Time-resolved PL measurements revealed that, under non-selective excitation conditions, additional carriers are provided from the surrounding layers to the quantum-well layers, especially at LT. Therefore, at RT, the PL efficiency does not correspond to the RRE under non-selective excitation conditions. We propose a model to explain carrier dynamics under the two excitation conditions showing that the PL efficiency equals the RRE under selective excitation conditions.
1 Kyoto University, Kyoto 615-8510, Japan
2 Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstr. 36, D-10623 Berlin Germany
3 Ferdinand-Braun-Institut, Gustav-Kirchhoff-Str. 4, D-12489 Berlin, Germany
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