Controlling Nanoscale Thermal Expansion of Monolayer Transition Metal Dichalcogenides by Alloy Engineering
Controlling Nanoscale Thermal Expansion of Monolayer Transition Metal Dichalcogenides by Alloy Engineering
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DOI：
10.1002/smll.201905892
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发表时间：
2019-12-12
期刊：
影响因子：
13.3
通讯作者：
Klie, Robert F.
中科院分区：
文献类型：
--
作者：
Hu, Xuan;Hemmat, Zahra;Klie, Robert F.
二维材料，如过渡金属二硫化物（TMDs）、石墨烯和氮化硼，被视为未来高功率/高频电子产品的有前途的材料。然而，这些二维材料之间的热膨胀系数（TEC）差异很大，这对单层材料纳米器件的设计构成了严峻的挑战。为了应对这一挑战，tmd的合金工程被用于定制其tec。本文采用扫描透射电镜原位加热实验，结合电子能量损失谱和第一性原理建模，对不同合金浓度的单层Mo1-xWxS2进行了TEC测定。TEC的显著变化被认为是Mo1-xWxS2中化学成分的函数，最小的TEC被报道为具有最高熵的构型。这项研究为理解控制二维材料TEC值的纳米级现象提供了关键见解。
2D materials, such as transition metal dichalcogenides (TMDs), graphene, and boron nitride, are seen as promising materials for future high power/high frequency electronics. However, the large difference in the thermal expansion coefficient (TEC) between many of these 2D materials could impose a serious challenge for the design of monolayer-material-based nanodevices. To address this challenge, alloy engineering of TMDs is used to tailor their TECs. Here, in situ heating experiments in a scanning transmission electron microscope are combined with electron energy-loss spectroscopy and first-principles modeling of monolayer Mo1-xWxS2 with different alloying concentrations to determine the TEC. Significant changes in the TEC are seen as a function of chemical composition in Mo1-xWxS2, with the smallest TEC being reported for a configuration with the highest entropy. This study provides key insights into understanding the nanoscale phenomena that control TEC values of 2D materials.