Atomically thin layers of transition-metal dichalcogenides semiconductors, such as MoS, exhibit strong and circularly polarized light emission due to inherent crystal symmetries, pronounced spin-orbit coupling, and out-of-plane dielectric and spatial confinement. While the layer-by-layer confinement is well-understood, the understanding of the impact of in-plane quantization in their optical spectrum is far behind. Here, we report the optical properties of atomically thin MoS colloidal semiconductor nanocrystals. In addition to the spatial-confinement effect leading to their blue wavelength emission, the high quality of our MoS nanocrystals is revealed by narrow photoluminescence, which allows us to resolve multiple optically active transitions, originating from quantum-confined excitons (coupled electron-hole pairs). Surprisingly, in stark contrast to monolayer MoS, the luminescence of the lowest-energy levels is linearly polarized and persists up to , meaning that it could be exploited in a variety of light-emitting applications.
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http://dx.doi.org/10.1021/acsnano.9b05656 | DOI Listing |
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