Evolution of Raman and photoluminescence spectral characteristics of monolayer CVD-MoS2 over a wide temperature range

• Published in: Vibrational spectroscopy 2022-11, Vol.123, p.103443, Article 103443
• Main Authors: Ibrahim, Wonge Lisheshar, Öper, Merve, Şar, Hüseyin, Ay, Feridun, Perkgöz, Nihan Kosku
• Format: Article
• Language: English
• Subjects: And thermal coefficient; CVD; Excitons; Monolayer Molybdenum disulphide; Phonons; Raman and PL spectroscopy
• ISSN: 0924-2031; 1873-3697
• DOI: 10.1016/j.vibspec.2022.103443

In this study, the temperature-dependent characteristics of monolayer MoS2 flakes produced by chemical vapor deposition (CVD) are examined at temperatures ranging from 83 to 483 K. The effect of temperature change on chemical vapor deposited MoS2 flakes transferred from glass to Si/SiO2 substrates using a modified PMMA assisted method, is also investigated using µ-Raman and photoluminescence spectroscopy. Our results show that the thermal coefficient of the A1 g Raman mode, which is inversely proportional to thermal conductivity, decreases from − 0.01275 to – 0.01352 cm−1 K−1 after the transfer process. The photoluminescence (PL) spectral intensity of both samples (i.e., as-grown on glass substrates and transferred on 300 nm Si/SiO2) is observed to fall with an increase in temperature and the bandgap decreased from 1.90 eV to 1.86 eV for the as-grown sample and from 1.85 to 1.81 eV for the transferred sample. The PL and Raman spectral analysis results show that the vibrational and excitonic properties of 2D MoS2 flakes are not substantially affected by transfer from one substrate to another. Monolayer MoS2 samples are also observed to be unaffected by temperatures as high as 583 K.