标题： 量子点集合电容-电压光谱的定量理解 显示英文标题

标题： Towards quantitative understanding of quantum dot ensemble capacitance-voltage spectroscopy

摘要： 非均匀的量子点（QD）集合与电荷库耦合，已通过例如电学方法如电容-电压谱学广泛研究。 我们展示了量子点电容随变化参数（如交流频率和浴温度）的实验测量结果。 实验揭示了电容峰位置的显著位移。 虽然温度引起的位移已被先前模型解释，但频率依赖的位移尚未被解释。 鉴于现有模型在解释这些现象方面存在不足，我们提出了一种基于主方程方法的改进理论模型，该模型包含了能量依赖的隧穿效应。 该方法成功地再现了实验数据。 我们强调了能量依赖的隧穿在两个不同区域中的关键作用：在低温下，由不同尺寸量子点的能量级分散引起的集合效应主导光谱响应；在高温和高频下，我们观察到一种不同性质的峰位移，这最好通过优化连续的入射和出射隧穿事件的联合概率来描述。 我们的发现有助于更深入地理解隧穿过程以及与共同库耦合的量子点集合的物理特性，对它们在单光子源和自旋量子比特等应用中的发展具有重要意义。 显示英文摘要

摘要： Inhomogeneous ensembles of quantum dots (QDs) coupled to a charge reservoir are widely studied by using, e.g., electrical methods like capacitance-voltage spectroscopy. We present experimental measurements of the QD capacitance as a function of varying parameters such as ac frequency and bath temperature. The experiment reveals distinct shifts in the position of the capacitance peaks. While temperature-induced shifts have been explained by previous models, the observation of frequency-dependent shifts has not been explained so far. Given that existing models fall short in explaining these phenomena, we propose a refined theoretical model based on a master equation approach which incorporates energy-dependent tunneling effects. This approach successfully reproduces the experimental data. We highlight the critical role of energy-dependent tunneling in two distinct regimes: at low temperatures, ensemble effects arising from energy-level dispersion in differently sized QDs dominate the spectral response; at high temperatures and frequencies, we observe a peak shift of a different nature, which is best described by optimizing the conjoint probability of successive in- and out-tunneling events. Our findings contribute to a deeper understanding of tunnel processes and the physical properties of QD ensembles coupled to a common reservoir, with implications for their development in applications such as single-photon sources and spin qubits.