Persistent photoconductivity of GaAs/AlGaAs heterostructures has hampered the measurement of charge- and spin-related quantum effects in gate-defined quantum devices and integrated charge sensors due to Si-dopant-related deep donor levels (DX centers). In this study, this effect is overcome by using an undoped GaAs/AlGaAs heterostructure for photonic purposes. We also measure the electron transport before and after LED illumination at low temperatures. In addition to a regular rapid saturation showing the increased carrier density, a slow accumulation of illumination effects appeared when different top-gate voltages were applied during illumination, which indicated the redistribution of charge at the oxide–GaAs interface. This study provides interesting insights into the development of optically stable devices for efficient semiconductor quantum interfaces.

中文翻译：

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通过依赖顶栅的照明区分未掺杂的 GaAs/AlGaAs 量子阱中的持久效应

由于与 Si 掺杂剂相关的深施主能级（DX 中心），GaAs/AlGaAs 异质结构的持久光电导性阻碍了门定义量子器件和集成电荷传感器中电荷和自旋相关量子效应的测量。在这项研究中，通过将未掺杂的 GaAs/AlGaAs 异质结构用于光子目的来克服这种影响。我们还测量了低温下 LED 照明前后的电子传输。除了显示载流子密度增加的规则快速饱和外，在照明期间施加不同的顶栅电压时，照明效应的缓慢累积出现，这表明氧化物-GaAs界面处的电荷重新分布。