Zhang Run-Sen, Jiang Jin-Wu
Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.
Phys Chem Chem Phys. 2021 Dec 22;24(1):156-162. doi: 10.1039/d1cp04655a.
Because of their advanced properties inherited from their constituent atomic layers, van der Waals heterostructures such as graphene/MoS are promising candidates for many optical and electronic applications. However, because heat tends to be generated during the operation of nanodevices, thermal expansion is an important phenomenon to consider for the thermal stability of such heterostructures. In the present work, molecular dynamics simulations are used to investigate the thermal expansion coefficient of the graphene/MoS heterostructure, and how the unavoidable misfit strain affects that coefficient is revealed. The misfit strain can tune the thermal expansion coefficient by a factor of six, and this effect is quite robust in the sense that it is insensitive to the size or direction of the heterostructure. Further analysis shows that the misfit strain offers an efficient means of engineering thermally induced ripples, this being the key mechanism for how the misfit strain affects the thermal expansion coefficient. These findings provide valuable information about the thermal stability of van der Waals heterostructures and offer help for practical applications of nanodevices based on such heterostructures.
由于从其组成原子层继承的先进特性，诸如石墨烯/二硫化钼之类的范德华异质结构是许多光学和电子应用的有前途的候选材料。然而，由于在纳米器件运行期间往往会产生热量，热膨胀是考虑此类异质结构热稳定性时的一个重要现象。在本工作中，使用分子动力学模拟来研究石墨烯/二硫化钼异质结构的热膨胀系数，并揭示不可避免的失配应变如何影响该系数。失配应变可将热膨胀系数调整六倍，并且从对异质结构的尺寸或方向不敏感的意义上来说，这种效应相当稳健。进一步分析表明，失配应变提供了一种设计热致波纹的有效方法，这是失配应变影响热膨胀系数的关键机制。这些发现提供了有关范德华异质结构热稳定性的有价值信息，并为基于此类异质结构的纳米器件的实际应用提供了帮助。
