Hong Yang, Ju Ming Gang, Zhang Jingchao, Zeng Xiao Cheng
Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
Phys Chem Chem Phys. 2018 Jan 24;20(4):2637-2645. doi: 10.1039/c7cp06874c.
Combining the best of different monolayers in one ultimate van der Waals (vdW) heterostructure is an appealing approach for practical applications. Recently, a graphene (GR) and molybdenum diselenide (MoSe) heterobilayer was successfully fabricated experimentally. The superior electrical conductivity of GR combined with the unique photoelectrical properties and direct bandgap of MoSe can yield many potential applications, such as Li-ion batteries, tunneling field effect transistors and two-dimensional non-volatile memory devices. Efficient heat conduction within the device components is of great importance for nanoelectronic performance. In this work, the cross-plane interfacial thermal resistance (R) and in-plane thermal conductivity (κ) of the GR/MoSe vdW heterobilayer are systematically investigated using classical molecular dynamics (MD) simulations. The predicted R at a temperature of 300 K is equal to 1.91 × 10 K m W. Effects of several modulators such as temperature, contact pressure and vacancy defects are evaluated, which are all found to have negative correlations with the calculated interfacial thermal resistance. The highest reduction of R amounts to 75% for doubled coupling strength between GR and MoSe. Spectral energy density (SED) and phonon density of states (Ph-DOS) analyses are performed to gain further insights into the phonon properties of GR and MoSe. Our study provides reasonable guidelines to increase heat dissipation efficiency for future GR/MoSe based applications.
将不同单层的最佳特性整合到一个终极范德华（vdW）异质结构中，是一种极具吸引力的实际应用方法。最近，石墨烯（GR）和二硒化钼（MoSe）异质双层已通过实验成功制备。GR的卓越导电性与MoSe独特的光电特性和直接带隙相结合，可产生许多潜在应用，如锂离子电池、隧穿场效应晶体管和二维非易失性存储器件。器件组件内的高效热传导对纳米电子性能至关重要。在这项工作中，使用经典分子动力学（MD）模拟系统地研究了GR/MoSe vdW异质双层的跨平面界面热阻（R）和面内热导率（κ）。在300 K温度下预测的R等于1.91×10 K m²/W。评估了温度、接触压力和空位缺陷等几种调制器的影响，发现它们与计算出的界面热阻均呈负相关。对于GR和MoSe之间耦合强度加倍的情况，R的最大降低幅度达到75%。进行了光谱能量密度（SED）和声子态密度（Ph-DOS）分析，以进一步深入了解GR和MoSe的声子特性。我们的研究为提高未来基于GR/MoSe的应用的散热效率提供了合理的指导方针。
