Abstract Quantum dot heterostructures with excellent low-noise properties became possible with high purity materials recently. We present a study on molecular beam epitaxy grown quantum wells and quantum dots with a contaminated aluminum evaporation cell, which introduced a high amount of impurities, perceivable in anomalies in optical and electrical measurements. We describe a way of addressing this problem and find that reconditioning the aluminum cell by overheating can lead to a full recovery of the anomalies in photoluminescence and capacitance-voltage measurements, leading to excellent low noise heterostructures. Furthermore, we propose a method to sense photo-induced trap charges using capacitance-voltage spectroscopy on self-assembled quantum dots. Excitation energy-dependent ionization of defect centers leads to shifts in capacitance-voltage spectra which can be used to determine the charge density of photo-induced trap charges via 1D band structure simulations. This method can be performed on frequently used quantum dot diode structures.

中文翻译：

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分子束扩散池质量对量子点和量子阱光学和电学性质的影响

摘要 近年来，高纯度材料使具有优异低噪声特性的量子点异质结构成为可能。我们提出了一项关于分子束外延生长的量子阱和量子点的研究，该量子阱和量子点被污染的铝蒸发池引入了大量杂质，可在光学和电学测量的异常中察觉。我们描述了一种解决这个问题的方法，并发现通过过热修复铝电池可以完全恢复光致发光和电容电压测量中的异常情况，从而产生出色的低噪声异质结构。此外，我们提出了一种在自组装量子点上使用电容电压光谱来感测光致陷阱电荷的方法。缺陷中心的激发能量依赖电离导致电容-电压谱的变化，可用于通过一维能带结构模拟确定光致陷阱电荷的电荷密度。这种方法可以在常用的量子点二极管结构上执行。