Theoretical study of time-resolved luminescence in semiconductors. IV. Lateral inhomogeneities
Theoretical study of time-resolved luminescence in semiconductors. IV. Lateral inhomogeneities
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DOI：
10.1063/1.4976102
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发表时间：
2017-02-28
影响因子：
3.2
通讯作者：
Scheer, Roland
中科院分区：
文献类型：
--
作者：
Maiberg, Matthias;Bertram, Frank;Scheer, Roland
在本系列的第四部分中，我们利用Synopsys (R) TCAD模拟和解析近似研究了横向不均匀性对脉冲激发后时间分辨发光衰减（TRL）的影响。本工作由两部分组成：第一部分研究了横向尺度上非均匀激励的影响。结果表明，在局域激发下，载流子可能存在强烈的横向扩散，从而限制了微trl实验的分辨率。在这种情况下，用均匀激励和平均光子密度代替模拟中的非均匀激励是不可能的，特别是由于缺陷饱和度非线性地依赖于激励。在第二部分中，我们考虑均匀激发并研究非均匀材料参数，即非均匀载流子寿命，带隙和掺杂密度。我们发现它们的效果强烈地依赖于它们的特征变异长度。对于小于扩散长度的长度尺度，不均匀的材料参数会导致弯曲的发光衰减。
In the fourth part of this series, we study the impact of lateral inhomogeneities on the time-resolved luminescence decay (TRL) after a pulsed excitation by means of simulation with Synopsys (R) TCAD and analytical approximation. This work consists of two parts: In the first part, the effect of excitations being inhomogeneous on a lateral scale is investigated. It turns out that for localized excitations there may be a strong lateral diffusion of charge carriers, thereby limiting the resolution of a micro-TRL experiment. In this case, a replacement of the inhomogeneous excitation in the simulation by a homogeneous excitation and an average photon density is not possible, especially due to defect saturation depending non-linearly on the excitation. In the second part, we consider a homogeneous excitation and study inhomogeneous material parameters, namely, inhomogeneous charge carrier lifetimes, band gaps, and doping densities. We find that their effects strongly depend on their characteristic lengths of variation. For length scales smaller than the diffusion length, inhomogeneous material parameters can lead to curved luminescence decays.