Thermal conductivity determination of suspended mono- and bilayer WS2 by Raman spectroscopy
thermal conductivity, tungsten disulfide, Raman, temperature dependence, excitation power
We report the thermal conductivities of monolayer (1L) and bilayer (2L) WS2 grown by chemical vapor deposition (CVD), which are determined by use of temperature and excitation dependences of 12g E and 1g A Raman modes. The first-order temperature coefficients of 12g E and 1g A modes in both supported and suspended WS2 layers were extracted. The frequency shift of the 1g A mode with temperature is larger than that of the 12g E mode for 1L-WS2, which is attributed to stronger electron–phonon coupling for the 1g A mode than that for the 12g E mode. Moreover, by use of the shift of the phonon mode induced by laser heating, the thermal conductivities at room temperature were estimated to be 32 and 53 W/(m·K) for 1L- and 2L-WS2, respectively. Our results provide fundamental information about the thermal properties of WS2 layers, which is crucial for developing applications of atomically-thin WS2 devices.
Tsinghua University Press
Namphung Peimyoo,Jingzhi Shang,Weihuang Yang,Yanlong Wang,Chunxiao Cong,Ting Yu, Thermal conductivity determination of suspended mono- and bilayer WS2 by Raman spectroscopy. NanoRes.2015, 8(4): 1210–1221