The intensity of photoluminescence (PL) changes when an additional below‐gap excitation (BGE) light modifies the electronic occupation of one of the crystalline defects acting as nonradiative recombination (NRR) levels and shifts the balance between radiative and NRR rates. The photon energy of above‐gap excitation (AGE) light selects the layer and determines the depth of inspection, whereas that of BGE corresponds to the energy distribution of the NRR levels. The essential advantage of two‐wavelength excited PL (TWEPL) lies on a systematic combination of BGE spectroscopy and AGE spectroscopy for a variety of materials. It provides the noncontacting and nondestructive detection of NRR levels, distributing in a whole wafer as well as in a microscopic volume. Density and the electron and hole capture rates of NRR level 1, N_t1, C_n1, and C_p1, and those of level 2, N_t2 and C_p2, are determined consistently by the TWEPL measurement with the aid of time‐resolved PL. A brief review is given on the principle of the TWEPL, basic model of analysis, and experimental results of detecting NRR levels in GaAs/AlGaAs, InGaAs/GaAs, InAs/GaAs, GaN, InGaN, AlGaN, and GaPN. The method gives us a guiding compass toward the efficiency improvement of electronic devices from which PL is observable.

中文翻译：

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两波长激发光致发光的非辐射复合能级的光谱学

当额外的低于间隙激发（BGE）的光改变了晶体缺陷之一的电子占据（作为非辐射复合（NRR）水平）并改变了辐射速率与NR​​R速率之间的平衡时，光致发光（PL）的强度就会改变。间隙以上激发（AGE）光的光子能量选择层并确定检查深度，而BGE的光子能量对应于NRR能级的能量分布。双波长激发PL（TWEPL）的主要优点在于BGE光谱和AGE光谱对各种材料的系统组合。它提供了NRR水平的非接触和非破坏性检测，可分布在整个晶片以及微观体积中。NRR 1级，N的密度以及电子和空穴捕获率_{t 1}， C _{n 1}和C _{p 1}以及2级， N _{t 2}和C _{p 2}均由TWEPL测量和时间分辨PL一致确定。简要介绍了TWEPL的原理，分析的基本模型以及检测GaAs / AlGaAs，InGaAs / GaAs，InAs / GaAs，GaN，InGaN，AlGaN和GaPN中NRR含量的实验结果。该方法为我们提供了可观察到PL的电子设备效率改进的指南针。