Controlled lateral quantum confinement in single-layer transition-metal chalcogenides (TMCs) can potentially combine the unique properties of two-dimensional (2D) exciton with the size-tunability of exciton energy, creating the single-layer quantum dots (SQDs) of 2D TMC materials. However, exploring such opportunities has been challenging due to the limited ability to produce well-defined SQDs with sufficiently high quality and size control, in conjunction with the commonly observed inconsistency in the optical properties. Here, we report an effective method to synthesize high-quality and size-controlled SQDs of WSe2 via multilayer quantum dots (MQDs) precursors, which enables grasping a clear picture of the role of lateral confinement on the optical properties of the 2D exciton. From the single-particle optical spectra and polarization anisotropy of WSe2 SQDs of varying sizes in addition to their ensemble data, we reveal how the properties of 2D exciton in single-layer TMCs evolve with increasing lateral quantum confinement.
Bibliographical noteFunding Information:
This work was supported by the Institute for Basic Science (IBS-R026-D1), the Asian Office of Aerospace Research and Development (FA2386-14-1-0014), the Welch Foundation (grant no. A-1639), NSF (grant no. DMR-1404457), and S. J. Yoo for TEM analyses [KBSI-HVEM (JEM-ARM1300S)].
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry