title: Measurement of Lateral and Interfacial Thermal Conductivity of Single- and Bilayer MoS2 and MoSe2 Using Refined Optothermal Raman Technique.
abstract: Atomically thin materials such as graphene and semiconducting transition metal dichalcogenides (TMDCs) have attracted extensive interest in recent years, motivating investigation into multiple properties. In this work, we demonstrate a refined version of the optothermal Raman technique to measure the thermal transport properties of two TMDC materials, MoS2 and MoSe2, in single-layer (1L) and bilayer (2L) forms. This new version incorporates two crucial improvements over previous implementations. First, we utilize more direct measurements of the optical absorption of the suspended samples under study and find values ∼40% lower than previously assumed. Second, by comparing the response of fully supported and suspended samples using different laser spot sizes, we are able to independently measure the interfacial thermal conductance to the substrate and the lateral thermal conductivity of the supported and suspended materials. The approach is validated by examining the response of a suspended film illuminated in different radial positions. For 1L MoS2 and MoSe2, the room-temperature thermal conductivities are 84 ± 17 and 59 ± 18 W/(m·K), respectively. For 2L MoS2 and MoSe2, we obtain values of 77 ± 25 W and 42 ± 13 W/(m·K). Crucially, the interfacial thermal conductance is found to be of order 0.1-1 MW/m(2) K, substantially smaller than previously assumed, a finding that has important implications for design and modeling of electronic devices.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Applied Physics, Stanford University , Stanford, California 94305, United States.
authors.forename: Dezheng
authors.initials: D
authors.lastname: Sun
authors.affiliation: Department of Applied Physics, Stanford University , Stanford, California 94305, United States.
authors.forename: Yilei
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, Yonsei University , Seoul 120-749, Korea.
authors.forename: Gwan-Hyoung
authors.initials: GH
authors.lastname: Lee
authors.forename: Xu
authors.initials: X
authors.lastname: Cui
authors.forename: Daniel
authors.initials: D
authors.lastname: Chenet
authors.forename: Yumeng
authors.initials: Y
authors.lastname: You
authors.affiliation: Department of Applied Physics, Stanford University , Stanford, California 94305, United States.
authors.forename: Tony F
authors.initials: TF
authors.lastname: Heinz
authors.forename: James C
authors.initials: JC
authors.lastname: Hone
keywords: Raman; molybdenum diselenide; molybdenum disulfide; thermal conductivity; thermal interface conductance