Phonon Anharmonicity of Tungsten Disulfide

• Published in: Journal of physical chemistry. C 2019-10, Vol.123 (41), p.25509-25514
• Main Authors: Peng, Ya-Kang, Cao, Zi-Yu, Chen, Liu-Cheng, Dai, Ning, Sun, Yan, Chen, Xiao-Jia
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.9b07553

Recent studies demonstrate that 2H-WS2 is an excellent candidate for further applications in the electronics, spintronics, and optoelectronics. The details of phonon scattering processes associated with the thermal properties of a material are crucial for commercial applications. Here, we report an experimental study of the temperature-dependent Raman spectra of 2H-WS2 over a wide range from 3.6 to 850 K. The nonlinear temperature-dependent behavior corresponding to the phonon anharmonicity is estimated from both the frequency and linewidth of E2g 2, E2g 1, and A1g modes. It is found that the three-phonon process is dominant in the phonon softening and linewidth broadening in the whole temperature range. The four-phonon process can be detected and is even stronger than the three-phonon process at high temperatures. The obtained E2g 1 mode is insensitive to the anharmonic effect, whereas the E2g 2 mode is most sensitive. The phonon anharmonicity is suggested to mainly originate from the interaction between acoustic phonon and optical phonon. Understanding the phonon anharmonicity in 2H-WS2 is helpful for further applications of nanodevices.