Changes in the Raman spectra of monolayer MoS₂ upon thermal annealing

Abstract

Defects have crucial effects on the electronic and optoelectronic properties of two‐dimensional materials. In this work, we measured the changes in the Raman spectra and electrical conductance of monolayer molybdenum disulfide (MoS2) with increasing defects via thermal annealing in a reducing atmosphere. Raman spectra of the basal plane MoS2 on SiO2 differed from those of the edge and revealed intricate changes upon annealing up to 550°C due to the substitution of adsorbed molecules and the creation of highly concentrated defects. On the other hand, MoS2 on hexagonal boron nitride (h‐BN) presented homogenous Raman spectra over the entire area and showed no noticeable changes in its Raman spectra upon annealing. For MoS2 on h‐BN, the charge transfer between MoS2 and adsorbed molecules and the number of defects created by annealing up to 550°C are not sufficient to change the Raman spectra. The distinct behaviors of the two sample spectra are ascribed to different substrate‐induced doping and interfacial adhesion strengths.

Surface Modification of Monolayer MoS2 by Baking for Biomedical Applications

“…Two characteristic vibrational peaks were observed for the MoS 2 film, namely the in-plane vibration mode (385 cm −1 ) and the out-of-plane vibration mode A 1g (403 cm −1 ) ( Figure 3A ). The wavenumber difference (Δ = 17.9 cm −1 ) between the peaks' positions is consistent with the presence of the monolayer MoS 2 domains (Kim et al, 2018 ). Figures 3B,C shows the changes in the frequency shift and full width at half-maximum (FWHM) of two modes with the increase in the baking temperature, respectively.…”

Defect-Inducedin SituAtomic Doping in Transition Metal Dichalcogenides via Liquid-Phase Synthesis toward Efficient Electrochemical Activity

“…This is attributed to lattice symmetry breaking in the crystal structure of the vacancyinduced MoS 2 . 36 In addition, the decrease of absorption peaks in vacancy-induced MoS 2 further verifies that sulfur vacancies are successfully introduced in MV-and HV-MoS 2 (Figure S7). 37 To gain more insights into the sulfur vacancy modulation, atomic-resolution annular dark-field scanning transmission electron microscopy (ADF-STEM) was conducted on the high-crystalline HV-MoS 2 and LV-MoS 2 films.…”

Physico-Mechanical Properties of Metal Matrix Self-Lubricating Composites Reinforced with Traditional and Nanometric Particles

“…In the MoS 2 and MoS 2 nanometric powder Raman spectra, Figure 7B, C, the in-plane E 2g at 382 cm −1 and the out-of-plane A 1g at 407 cm −1 Raman modes of MoS 2 exhibited the strongest signals of the whole spectra, as expected [61][62][63]. The E 1g mode near 286 cm −1 was also present [62].…”