Project Summary: 2D semiconductors are promising candidates for quantum information processes and offer the possibility of achieving in-plane exciton confinement, similar to zero-dimensional quantum dots, with intriguing optical and electronic properties via strain or composition engineering. However, realizing such laterally confined 2D dots and systematically controlling their size is challenging. Here, we report the observation of lateral confinement of excitons in in-plane MoSe2quantum dots (~15-60 nm wide) inside a matrix of WSe2monolayer film via a sequential epitaxial growth process. Optical spectroscopy reveals size-dependent exciton confinement in the MoSe2monolayer quantum dots with exciton blue shift (12-40 meV) at 80k as compared to continuous monolayer MoSe2. Single-photon emission (g2(0) ~ 0.4) was also observed from the smallest dots at 1.6 K. Our study opens the door to compositionally engineered, tunable, in-plane quantum light sources in 2D semiconductors.
Publication: G. Kim et al., Nature Comm. 15, 6361 (2024). 10.1038/s41467-024-50653-x; Instruments 10.60551/znh3-mj13; Data 10.26207/0ddt-qt82
2DCC Role:The epitaxial growth process to produce the in-plane MoSe2/WSe2 quantum dot heterostructures was developed in the 2DCC MOCVD facility in collaboration with Prof. Deep Jariwala’s group at UPenn.