Many-body effects in doped WS2 monolayer quantum disks at room temperature

Abstract

Due to strong Coulomb interactions, reduced screening effects, and quantum confinement, transition-metal dichalcogenide (TMD) monolayer quantum disks (MQDs) are expected to exhibit large exciton binding energy, which is beneficial for the investigation of many-body physics at room temperature. Here, we report the first observations of room-temperature many-body effects in tungsten disulfide (WS 2 ) MQDs by both optical measurements and theoretical studies. The band-gap renormalization in WS 2 MQDs was about 250 ± 15 meV as the carrier density was increased from 0.6(±0.2) × 10 12 to 8.3(±0.2) × 10 12 cm −2 . We observed a striking exciton binding energy as large as 990 ± 30 meV at the lowest carrier density, which is larger than that in WS 2 monolayers. The huge exciton binding energy in WS 2 MQDs is attributed to the extra quantum confinement in the lateral dimension. The band-gap renormalization and exciton binding energies are explained using efficient reduced screening. On the basis of the Debye screening formula, the Mott density in WS 2 MQDs was estimated to be~3.95 × 10 13 cm −2 . Understanding and manipulation of the many-body effects in two-dimensional materials may open up new possibilities for developing exciton-based optoelectronic devices.npj 2D Materials and Applications (2019) 3:46 ; https://doi.

Ultrafast nonequilibrium dynamic process of separate electrons and holes during exciton formation in few-layer tungsten disulfide

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Exciton‐Dominated Ultrafast Optical Response in Atomically Thin PtSe2

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Mechanisms and Applications of Steady-State Photoluminescence Spectroscopy in Two-Dimensional Transition-Metal Dichalcogenides

“…), stability (temperature, air, light, electric field, etc. ), − defects, − doping densities, − gating voltage dependencies, − heterostructures (charge transport behaviors, types, and quality), − device performance (light-emitting diodes (LEDs), solar cells, photodetectors, etc . ), and many others.…”