Photovoltaic Response and Charge Redistribution Processes in GaAs/AlGaAs Multiple‐Quantum Wells Structure,Physica Status Solidi (B) - Basic Solid State Physics

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Photovoltaic Response and Charge Redistribution Processes in GaAs/AlGaAs Multiple‐Quantum Wells Structure
Physica Status Solidi (B) - Basic Solid State Physics ( IF 1.5 ) Pub Date : 2020-08-07 , DOI: 10.1002/pssb.202000331
Subhomoy Haldar _{1,

2} , Shailendra Kumar ₃ , Rijul Roychowdhury _{1,

2} , Vijay Kumar Dixit _{1,

2}

Affiliation

The impact of radiative and non‐radiative processes on the photovoltaic response of GaAs/AlGaAs multiple‐quantum wells is investigated by temperature, excitation power, and chopping‐frequency‐dependent surface photovoltage (SPV) measurements. It is shown that a systematic study of SPV amplitude along with phase spectra can provide important information on thermal escape, carrier localization, and spatial redistribution of charge carriers. Characteristic features in SPV‐phase spectra related to quantum well (QW) transitions and their variation under an external perturbation are explained by the electron–electron interaction. It is found that a many‐body interaction inside the QW is responsible for the capture of charges at the heterointerfaces, which builds up an interface electric field and hinders the drift/diffusion of charges. Such an effect becomes dominant under higher excitation powers, causing a sub‐linear enhancement of photovoltage amplitude and an increase in phase delay as a function of photon flux. From the chopping‐frequency‐dependent SPV measurements, it is concluded that carriers during the drift in barrier layers are repeatedly captured by point defects and other QWs, which enhances the effective time response of the photovoltage signal. Results obtained in this study are beneficial in the engineering of quantum structures for high‐efficiency photovoltaics and non‐invasive characterization of electro‐optical processes.

中文翻译：

GaAs / AlGaAs多量子阱结构中的光伏响应和电荷再分配过程

通过温度，激发功率和斩波频率相关的表面光电压（SPV）测量，研究了辐射过程和非辐射过程对GaAs / AlGaAs多量子阱光伏响应的影响。结果表明，对SPV振幅以及相谱的系统研究可以提供有关热逸出，载流子局部化和电荷载流子的空间重新分布的重要信息。SPV相光谱中与量子阱（QW）跃迁有关的特征及其在外部扰动下的变化通过电子-电子相互作用来解释。我们发现，量子阱内部的多体相互作用负责捕获异质界面上的电荷，从而形成了界面电场并阻碍了电荷的漂移/扩散。这种效应在较高的激励功率下变得占优势，导致光电压幅值亚线性增强，并且相位延迟随光子通量的增加而增加。从与斩波频率相关的SPV测量结果可以得出结论，势垒层漂移期间的载流子会被点缺陷和其他QW重复捕获，从而增强了光电压信号的有效时间响应。这项研究获得的结果有益于高效光伏的量子结构工程以及电光过程的非侵入式表征。结论是，在势垒层漂移期间的载流子被点缺陷和其他QW重复捕获，这增强了光电压信号的有效时间响应。这项研究获得的结果有益于高效光伏的量子结构工程以及电光过程的非侵入式表征。可以得出结论，势垒层漂移期间的载流子会被点缺陷和其他QW重复捕获，从而增强了光电压信号的有效时间响应。这项研究中获得的结果有益于高效光伏的量子结构工程以及电光过程的非侵入式表征。

更新日期：2020-08-07

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