Abstract In this work, the authors have investigated the optical and morphological characteristics of uncapped InAs quantum dots (QDs) and their sensitivity to the surface passivation. The temperature dependent carrier transfer mechanism between self-assembled vertically coupled InAs surface quantum dot (SQD) and underneath buried quantum dot (BQD), separated by a thin spacer layer is investigated. Oxide layer etching followed by surface passivation has been carried out to deplete the surface states and improve the structural/optical behaviour of uncapped InAs SQDs. The passivation time has been varied from 0.5 to 2.5 h and its effect on the optical and morphological properties is investigated. The larger SQDs are resized to smaller ones and show lower size dispersion after the etching process. Additionally, an increased energy level overlapping between SQD and BQD is obtained after the etching process. This partial overlap of energy levels further corroborates the enhanced electronic communication achieved between the surface and underneath buried dots. The sample, with 1 h of surface passivation, unveils as the best among all in terms of stronger luminescence from the SQD. Through this study, the SQDs are projected as the primary receptor, whereas the BQDs behave like carrier reservoirs. Hence, the BQDs would provide the carriers to enhance the sensitivity of the SQDs, which would impact the performance of QD based sensors.

中文翻译：

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通过非原位表面态钝化改善垂直耦合表面和埋入 InAs Stranski-Krastanov 量子点系统中的载流子转移

摘要 在这项工作中，作者研究了无帽 InAs 量子点 (QD) 的光学和形态特征及其对表面钝化的敏感性。研究了自组装垂直耦合 InAs 表面量子点 (SQD) 和下方掩埋量子点 (BQD) 之间的温度相关载流子转移机制，由薄间隔层隔开。已经进行了氧化层蚀刻和表面钝化，以耗尽表面状态并改善未覆盖的 InAs SQD 的结构/光学行为。钝化时间从 0.5 到 2.5 小时不等，并研究了其对光学和形态特性的影响。较大的 SQD 被调整为较小的尺寸，并在蚀刻工艺后显示出较低的尺寸分散。此外，在蚀刻工艺之后获得了 SQD 和 BQD 之间增加的能级重叠。能级的这种部分重叠进一步证实了在表面和下面埋点之间实现的增强的电子通信。表面钝化时间为 1 小时的样品在 SQD 发出的更强发光方面表现最好。通过这项研究，SQDs 被预测为主要受体，而 BQDs 表现得像载体水库。因此，BQD 将提供载波以提高 SQD 的灵敏度，这将影响基于 QD 的传感器的性能。经过 1 小时的表面钝化，就 SQD 的更强发光而言，它是最好的。通过这项研究，SQDs 被预测为主要受体，而 BQDs 表现得像载体水库。因此，BQD 将提供载波以提高 SQD 的灵敏度，这将影响基于 QD 的传感器的性能。经过 1 小时的表面钝化，就 SQD 的更强发光而言，它是最好的。通过这项研究，SQDs 被预测为主要受体，而 BQDs 表现得像载体水库。因此，BQD 将提供载波以提高 SQD 的灵敏度，这将影响基于 QD 的传感器的性能。