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arXiv · 0807.5056

Origin of the Broad Lifetime Distribution of Localized Excitons in InGaN/GaN Quantum Dots

M. Winkelnkemper·M. Dworzak·T. P. Bartel·A. Strittmatter·A. Hoffmann·D. Bimberg
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Abstract

We derive an energy-dependent decay-time distribution function from the multi-exponential decay of the ensemble photoluminescence (PL) of InGaN/GaN quantum dots (QDs), which agrees well with recently published single-QD time-resolved PL measurements. Using eight-band k.p modelling, we show that the built-in piezo- and pyroelectric fields within the QDs cause a sensitive dependence of the radiative lifetimes on the exact QD geometry and composition. Moreover, the radiative lifetimes also depend heavily on the composition of the direct surrounding of the QDs. A broad lifetime distribution occurs even for moderate variations of the QD structure. Thus, for unscreened fields a multi-exponential decay of the ensemble PL is generally expected in this material system.

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M. Winkelnkemper, M. Dworzak, T. P. Bartel, A. Strittmatter, A. Hoffmann, D. Bimberg. 2008-07-31. Origin of the Broad Lifetime Distribution of Localized Excitons in InGaN/GaN Quantum Dots. https://doi.org/10.1002/pssb.200844129

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