Han Pingping, Du Tingli, Zhou Si, Zhao Jijun
Key Laboratory of Materials Modification by Laser, Ministry of Education, Ion and Electron Beams (Dalian University of Technology), Dalian, 116024, China.
Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou, 510006, China.
Small Methods. 2025 May 3:e2402262. doi: 10.1002/smtd.202402262.
Electric-field tuning of excitonic states in confined systems via the quantum-confined Stark effect (QCSE) provides a flexible way for electro-optic modulation with great efficiency. In epitaxial and colloidal quantum dots (QDs), the interdot coupling allows additional degrees of freedom for optical switches. Here QCSE is explored in artificial molecules formed by two coupled QDs of main group II-VI elements. Compared with a single QD, the QCSE is remarkably enhanced in QD molecules and highly tunable by the interdot coupling strength as well as by homo- and hetero-dimerization of QDs. In addition, the strong coupling between QDs can retard charge separation under an external electric field and even bring the electron and hole states from two QDs into a resonance, thereby boosting the fluorescence emission in QD molecules. These mechanistic understandings provide vital guidelines for fine manipulation of electron, spin, and exciton in coupled QDs and their assemblies for tunable optoelectronics, photonics, and quantum information applications.
通过量子限制斯塔克效应（QCSE）对受限系统中的激子态进行电场调谐，为高效电光调制提供了一种灵活的方式。在外延量子点和胶体量子点（QD）中，点间耦合为光开关提供了额外的自由度。本文研究了由主族II-VI元素的两个耦合量子点形成的人工分子中的QCSE。与单个量子点相比，量子点分子中的QCSE显著增强，并且可以通过点间耦合强度以及量子点的同二聚化和异二聚化进行高度调谐。此外，量子点之间的强耦合可以在外部电场下延迟电荷分离，甚至使两个量子点的电子和空穴态发生共振，从而增强量子点分子中的荧光发射。这些机理理解为在耦合量子点及其组件中精细操纵电子、自旋和激子以用于可调谐光电子学、光子学和量子信息应用提供了重要指导。
