Phonon Scattering in Monolayer Molybdenum Disulfide under Different Defect Concentrations Based on Temperature-Dependent Raman Spectra

Abstract

Monolayer molybdenum disulfide (MoS2), among other two-dimensional transition-metal dichalcogenides materials, is widely used in a broad range of industries due to its extraordinarily different material properties compared to its bulk counterpart. However, such unique behavior may be greatly affected by its capacity of energy dissipation or heat conduction, largely attributed to its inherent phonon scattering properties. In addition, the phonon properties of MoS2 may be greatly affected by parameters such as temperature, defect concentration, etc., reflected by the Raman spectra evolution of A1g or E2g peaks. In this light, we analyze the combined influences of temperature and defect concentration on phonon scattering for the first time. We specifically elaborate experiments based on the temperature-dependent Raman spectroscopy in order to characterize the effect of defects on phonon scattering properties of MoS2. On this basis, a predictive model is developed for the estimation of phonon lifetime under different defect concentrations that may be served as a brief yet accurate and efficient designer tool in the early stage of defect/phonon engineering. In addition, our study may provide more physical insights toward a comprehensive understanding of the phonon behavior of MoS2, thus paving a way for more practical application potentials enabled by low-dimensional materials.