Origin of the broad lifetime distribution of localized excitons in InGaN/GaN quantum dots
Origin of the broad lifetime distribution of localized excitons in InGaN/GaN quantum dots
复制标题
InGaN/GaN 量子点中局域激子的宽寿命分布的起源
DOI：
10.1002/pssb.200844129
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
D. Bimberg
中科院分区：
文献类型：
--
作者：
M. Winkelnkemper;M. Dworzak;T. Bartel;A. Strittmatter;A. Hoffmann;D. Bimberg
我们从InxGa 1-xN/GaN量子点（QD）的系综光致发光（PL）的多指数衰减导出了能量依赖的衰减时间分布函数，这与最近发表的单QD时间分辨PL测量结果吻合得很好。使用八带k · p模型，我们表明量子点内的内置压电场和热释电场导致辐射寿命对精确量子点几何形状和组成的敏感依赖性。此外，辐射寿命也很大程度上取决于量子点的直接周围的组成。宽的寿命分布甚至对于QD结构的适度变化也会发生。因此，对于未屏蔽场，在该材料系统中通常预期系综PL的多指数衰减。（© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
We derive an energy‐dependent decay‐time distribution function from the multi‐exponential decay of the ensemble photoluminescence (PL) of Inx Ga1–x N/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. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)