Temperature- and power-dependent phonon properties of suspended continuous WS₂ monolayer films

This manuscript reports temperature- and power-dependence of in-plane E¹_2g and out-of-plane A_1g Raman modes in a continuous WS₂ monolayer film (CWMF) prepared using low pressure chemical vapor deposition (LPCVD), suspended on a perforated substrate. The frequencies of these two phonon modes vary linearly with temperature (77–523 K) and power (2–14 μW), and the modes soften as local temperature increases. The first-order temperature coefficients for E¹_2g and A_1g modes are 0.0124 and 0.0112 cm⁻¹/K, respectively, and power coefficients are 0.1228 and 0.1381 cm⁻¹/μW. Using the 1D Balandin's approach, we have calculated the thermal conductivity of the suspended CWMF at room temperature to be ca. 20 and 16 W/mK when considering the E¹_2g and A_1g modes, respectively. Our results provide thermal properties values of CWMF, which are very important for developing monolayer WS₂ electronic devices.