基于硅锗异质结的二维量子点阵列的制备与表征

硅基半导体量子点中的自旋量子比特近几年来发展迅速，其单比特门与两比特门操作保真度已经突破了容错量子计算的阈值.在此基础上，如何构建硅基量子点二维阵列变得广受学界关注，然而二维阵列复杂的结构在器件制备和测量上均带来挑战.本文设计并成功制备了一种Si/SiGe异质结上的2×4结构八量子点二维阵列器件.借助输运测量方法测量了八量子点器件的全部电荷稳定性相图，并进一步地使用电荷感应调制测量方法得到了器件内的少电子区电荷稳定性相图，说明了对量子点电荷态的高灵敏度探测能力.此外，通过调控势垒电极展示了对量子点间隧穿耦合的调控作用并测量了多量子点耦合的电荷稳定性相图.本文的研究结果展示了使用Si/SiGe异质结构建自旋量子比特二维阵列的潜力，为未来硅量子点二维阵列的进一步扩展提供经验与参考.

Fabrication and Characterization of Two Dimensional Quantum Dot Array based on Si/SiGe Heterostructure

In recent years, there has been rapid development in the field of spin qubits in silicon semiconductor quantum dots. The fidelity of both single-qubit and two-qubit gate operations has surpassed the threshold for fault- tolerant quantum computing. With these progresses, the construction of silicon-based quantum dot two-dimensional arrays has gathered significant attention in the research community. However, the complex structure of two- dimensional arrays poses challenges in both device fabrication and measurement. This paper presents the design and successful fabrication of a 2 X 4 structured eight-quantum-dot two-dimensional array device on a Si/SiGe heterostructure. Using transport measurement method, we have measured the full charge stability diagram of the 2 X4 eight-quantum-dot device. Furthermore, we have employed charge sensing modulation measurement method to obtain multiple single-electron region charge stability diagrams within the device, which demonstrates the high sensitivity of charge states detection. Additionally, we demonstrated control over tunnel coupling between quantum dots by modulating barrier electrodes and measured the charge stability diagrams of multi-quantum dot. The device demonstrates the potential of constructing a two-dimensional qubit array using Si/SiGe heterostructures, providing valuable experience and references for the future expansion of silicon quantum dot two-dimensional arrays.