Resonance effects in the Raman scattering of monolayer and few-layerMoSe2

Abstract

Using resonant Raman scattering spectroscopy with 25 different laser lines, we describe the Raman scattering spectra of mono-and multi-layers 2H-molybdenum diselenide (MoSe2) as well as the different resonances affecting the most pronounced features. For high-energy phonons, both A-and E-symmetry type phonons present resonances with A and B excitons of MoSe2 together with a marked increase of intensity when exciting at higher energy, close to the C exciton energy. We observe symmetry dependent exciton-phonon coupling affecting mainly the low-energy rigid layer phonon modes. The shear mode for multilayer displays a pronounced resonance with the C exciton while the breathing mode has an intensity that grows with the excitation laser energy, indicating a resonance with electronic excitations at energies higher than that of the C exciton.

Phonon-assisted oscillatory exciton dynamics in monolayer MoSe2

“…The dominant feature in the X 0 PLE is the average oscillation period of 18.5 meV. From recent studies of Raman scattering on monolayer MoSe 2 , 25,27 this period matches that of the M-point longitudinal acoustic phonon, LA(M). Figure 3a shows the locations of M points in the Brillouin zone.…”

“…Their sub-meV linewidths are consistent with "conventional" Raman spectra measured on a different monolayer MoSe 2 sample (Supplementary Discussion), as well as with those reported in the literature. [25][26][27] The combined spectral features of PL emission and Raman scattering give rise to the overall emission spectrum, as shown in the example of Fig. 2b.…”

Rhenium Diselenide (ReSe2) Near‐Infrared Photodetector: Performance Enhancement by Selective p‐Doping Technique

“…This is because the distorted triclinic structure of ReSe 2 caused 18 Raman-active vibration modes, [19] unlike group IV TMDs with an isotropic hexagonal structure (e.g., MoS 2 , WSe 2 , MoSe 2 , and WS 2 ). [20][21][22][23] When 10 m HCl was applied to the ReSe 2 , all the Raman peaks were slightly blue-shifted (gray solid line → red dotted line). This is likely because the in-and out-of-plane vibrations of the ReSe 2 structure were intensified by the HCl treatment.…”

Recent advancement in the performance of solar cells by incorporating transition metal dichalcogenides as counter electrode and photoabsorber

“…The band gap of these materials lies in the range of 1.0 to 2.0 eV, which matches well with solar spectrum. This band gap is also comparable with the band gap of Si (1.1 eV), GaAs (1.4 eV), and CdTe (1.5 eV) . Furthermore, these monolayer TMDCs with direct band gap possess high mobility and excellent light absorption properties making them a promising candidate for high efficient PV applications .…”

“…This band gap is also comparable with the band gap of Si (1.1 eV), GaAs (1.4 eV), and CdTe (1.5 eV). 21,[33][34][35][36] Furthermore, these monolayer TMDCs with direct band gap possess high mobility 37,38 and excellent light absorption properties making them a promising candidate for high efficient PV applications. [39][40][41][42] The band gap, ionization potential, and electron affinity of these materials can be engineered by forming alloys such as Mo 1 − x W x S 2 43,44 and by applying mechanical stress.…”