Robust Excitons and Trions in Monolayer MoTe₂

Abstract

Molybdenum telluride (MoTe2) has emerged as a special member in the family of two-dimensional transition metal dichalcogenide semiconductors, owing to the strong spin-orbit coupling and relatively small energy gap, which offers new applications in valleytronic and excitonic devices. Here we successfully demonstrated the electrical modulation of negatively charged (X(-)), neutral (X(0)), and positively charged (X(+)) excitons in monolayer MoTe2 via photoluminescence spectroscopy. The binding energies of X(+) and X(-) were measured to be ∼24 and ∼27 meV, respectively.The exciton binding energy of monolayer MoTe2 was measured to be 0.58 ± 0.08 eV via photoluminescence excitation spectroscopy, which matches well with our calculated value of 0.64 eV.

Light-Matter Interactions in Two-Dimensional Transition Metal Dichalcogenides: Dominant Excitonic Transitions in Mono- and Few-Layer MoX$_2$ and Band Nesting

“…While the theoretical calculations in [35] yielded a G 0 W 0 band gap very similar to ours, they predicted a significantly higher exciton binding energy of about 0.6 eV that led to a good agreement of the simulated and predicted A peak energies and resembles the earlier results by Komsa et. al [50].…”

“…While a number of groups have studied MoS 2 in both its mono-and bilayer forms, simulations that include electron-hole effects are to date scarce for MoSe 2 [32,46,50] and MoTe 2 [35,46]. Figure S3 shows the obtained imaginary parts of the dielectric functions from our calculations.…”

Monolayer Single-Crystal 1T′-MoTe2 Grown by Chemical Vapor Deposition Exhibits Weak Antilocalization Effect

“…27 The spectrum agrees well with previous reports of few layer MoTe 2 in the 1T′ phase 21,22,28 and it differs significantly from the experimental spectrum for the 2H and theoretical 1T phase. 21,27,29 An additional predicted Raman-active mode 27 at 80.41 cm −1 is removed by the edge filter of the apparatus and is not expected to be observed. To our knowledge, this is the first experimental report of the peak at 269 cm −1 , which is expected to blueshift from 258 to 269 cm −1 as the material is reduced from bulk to monolayer.…”

Exploration of exciton behavior in atomically thin WS2 layers by ionic gating

“…7,11,[17][18][19][20][21] At a relatively low-level carrier doping obtained by conventional gating at equilibrium, the transitions among exciton, trion, and biexciton, 7,11 a decrease in the exciton binding energy, and the renormalization of a quasiparticle energy bandgap caused by screening the Coulomb interactions were studied. 21 Bandgap renormalization, carrier population inversion, and the absence of exciton peaks were observed in a nonequilibrium state in highly doped mono-and bilayer WS 2 excited by intense optical pump pulses, 22 indicating the emergence of a Mott transition (MT).…”

“…28 Note that the spectral weight is sensitive even to a slight change of carrier density, while the peak position is not sensitive to it at low gate voltages. 18,29 By fitting the data to Gaussian functions, we obtained the exciton, trion, and biexciton peak positions, as shown in Fig. 2(c).…”