1 research outputs found
Rydberg Excitons and Trions in Monolayer MoTe<sub>2</sub>
Monolayer
transition metal dichalcogenide (TMDC) semiconductors
exhibit strong excitonic optical resonances, which serve as a microscopic,
noninvasive probe into their fundamental properties. Like the hydrogen
atom, such excitons can exhibit an entire Rydberg series of resonances.
Excitons have been extensively studied in most TMDCs (MoS2, MoSe2, WS2, and WSe2), but detailed
exploration of excitonic phenomena has been lacking in the important
TMDC material molybdenum ditelluride (MoTe2). Here, we
report an experimental investigation of excitonic luminescence properties
of monolayer MoTe2 to understand the excitonic Rydberg
series, up to 3s. We report a significant modification of emission
energies with temperature (4 to 300 K), thereby quantifying the excitonâphonon
coupling. Furthermore, we observe a strongly gate-tunable excitonâtrion
interplay for all the Rydberg states governed mainly by free-carrier
screening, Pauli blocking, and band gap renormalization in agreement
with the results of first-principles GW plus BetheâSalpeter
equation approach calculations. Our results help bring monolayer MoTe2 closer to its potential applications in near-infrared optoelectronics
and photonic devices