Effects of alloying on in-plane thermal conductivity and thermal boundary conductance in transition metal dichalcogenide monolayers
Effects of alloying on in-plane thermal conductivity and thermal boundary conductance in transition metal dichalcogenide monolayers
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DOI：
10.1103/physrevmaterials.4.124006
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发表时间：
2020-12
影响因子：
3.4
通讯作者：
C. Foss;Z. Akšamija
中科院分区：
文献类型：
--
作者：
C. Foss;Z. Akšamija
二维1H过渡金属二硫属化物（TMD）提供了一个平台，类似于IV族立方半导体合金（${\mathrm{Si}}_{1\ensuremath{-}x}\mathrm{Ge}$），可以系统地研究合金化在二维材料系统中的影响。TMD合金的现有文献探讨了其电，磁和光学性能，但缺乏支持和纳米结构系统的热输运的综合分析。本文采用第一性原理驱动的声子玻尔兹曼输运理论和二维-三维热边界电导模型，系统地研究了悬浮和${\mathrm{SiO}}_{2}$支撑的单层TMD合金的面内和跨面声子输运.我们发现，合金TMD的热导率是依赖于系统的大小高达几十微米，质量差和基板散射的组合可以显着降低热传输，即使在大型系统（$g500$ nm）。除了面内输运，我们发现，热边界电导显示出质的不同的趋势和显着较弱的调制与合金成分相比，热导率。我们的研究结果有助于阐明二维单层TMD合金的面内和跨面热输运性质，并进一步研究其在纳米电子学、传感和能源器件中的应用。
Two-dimensional 1H transition metal dichalcogenides (TMDs) provide a platform, analogous to group IV cubic semiconductor alloys (${\mathrm{Si}}_{1\ensuremath{-}x}\mathrm{Ge}$), that enables systematic investigations on the effects of alloying in 2D material systems. The existing literature on TMD alloys explores their electrical, magnetic, and optical properties, but lacks a comprehensive analysis of thermal transport in supported and nanostructured systems. Here we employ first-principles-driven phonon Boltzmann transport formalism and a 2D-3D thermal boundary conductance model to systematically study in-plane and cross-plane phonon transport of suspended and ${\mathrm{SiO}}_{2}$ supported single-layer TMD alloys. We find that the thermal conductivity of alloyed TMDs is dependent on system size up to tens of microns and that the combination of mass-difference and substrate scattering can significantly reduce thermal transport even in large systems ($g500$ nm). Beyond in-plane transport, we find that the thermal boundary conductance displays a qualitatively different trend and significantly weaker modulation with alloy composition as compared to the thermal conductivity. Our results help shed light on the in-plane and cross-plane thermal transport properties of 2D single-layer TMD alloys and further their applications in nanoelectronics, sensing, and energy devices.