Controlled quantum-confined Stark effect in InP magic-size cluster by doping and aggregation

Abstract The quantum-confined Stark effect (QCSE) is a fundamental phenomenon in quantum dots (QDs) and quantum wells critical to electro-optic modulation. As a bridge between atoms and QDs, the magic-size clusters (MSCs) represent the ultimate in quantum-confined systems, whose response behavior to an external electric field remains largely unknown. Herein, for the first time, we investigate the QCSE in indium phosphide (InP) MSCs and consider the effects of heteroatom doping and inter-cluster coupling. Chemical modifications result in enhanced and highly tunable QCSE in InP MSCs, enabling controlled access to either linear or quadratic Stark shifts. In the coupled InP MSCs, the absorption spectrum is significantly enhanced and broadened in the visible region. The characteristic peaks are effectively tuned by the electric field and meanwhile can maintain the strong absorption and emission intensity owing to the inter-cluster coupling. These results not only fill the knowledge gap in the QCSE under extreme quantum confinement, but also provide valuable guidance for designing high-efficiency optical switches and related devices at atomic precision.