Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 1: Nitrides: Preparation and characterization I

HL 1.10: Talk

Monday, March 18, 2024, 12:15–12:30, EW 015

Point defect diffusion in GaInN/GaN quantum well structures — •Rodrigo De Vasconcellos Lourenco, Philipp Henning, Philipp Horenburg, Uwe Rossow, Heiko Bremers, and Andreas Hangleiter — Institute of Applied Physics, Technische Universität Braunschweig, Germany

A reduction of the point defect density in light-emitters based on GaInN/GaN quantum wells (QW) is desired for maximising the internal quantum efficiency. We investigate the non-radiative lifetime of GaInN/GaN single QWs grown on In-free and In-containing underlayers (UL). The non-radiative lifetime of SQWs increases with UL thickness in both cases. Since the non-radiative lifetime is inversely proportional to the defect density and as V-pits efficiently suppress the recombination at threading dislocations, our result suggests a point defect density profile over distance between the high temperature GaN buffer layer and the QW. Hence, a simple solution to the diffusion equation allows to accurately fit our data and yields a defect diffusion coefficient. point defect diffusion is a thermally activated process, associated with a defect migration barrier, which is in the range expected for the nitrogen vacancy in n-type GaN. Surprisingly, an attempt to reproduce the results lead to non-radiative lifetimes about one order of magnitude lower than previously, but with the same activation energy. This means that diffusion is prevalent in the same way, but with a different boundary condition, i.e. a higher density of point defects in the underlying GaN buffer.

Keywords: Point defect diffusion; Point defect; Underlayer; Internal quantum efficiency