ScholarWorks@숙명여자대학교

초록

We report low-frequency Raman scattering results of bilayer (2L) MoS2 structures with 3R and 2H stacking orders. The stacking orders were identified by Raman mapping images of the low-frequency shear (S) and layer breathing (B) modes. Linear temperature coefficients (?) were obtained from temperature-dependent frequency changes of the shear and layer breathing modes for the 3R- and 2H-stacked 2L MoS2: ?S3R = 0.011 ? 0.006cm- 1/K, ?S2H = - 0.009 ? 0.002cm- 1/K, ?B3R = - 0.009 ? 0.003cm- 1/K, and ?B2H = 0.010 ? 0.002 cm- 1/K. Interestingly, the temperature coefficients were significantly reduced after the MoS2 samples were thermally heated: ?S3R = - 0.004 ? 0.001cm- 1/K, ?S2H = - 0.004 ? 0.001cm- 1/K, ?B3R = 0.002 ? 0.001cm- 1/K, and ?B2H = - 0.002 ? 0.001cm- 1/K. Similar behaviors were also observed for the temperature coefficients of the high-frequency E12g and A1g phonons. The heating-induced modifications in the temperature coefficients are attributed to changes in the MoS2?substrate coupling. Our result further paves the way for optimal design strategies for low-dimensional device applications where thermal management plays a crucial role in device performance.

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