Yin Kaili, Shi Liping, Ma Xiaoliang, Zhong Yesheng, Li Mingwei, He Xiaodong
Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150080, China.
School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Nanomaterials (Basel). 2023 Jul 28;13(15):2196. doi: 10.3390/nano13152196.
Silicon carbide (SiC) is a promising material for thermoelectric power generation. The characterization of thermal transport properties is essential to understanding their applications in thermoelectric devices. The existence of stacking faults, which originate from the "wrong" stacking sequences of Si-C bilayers, is a general feature of SiC. However, the effects of stacking faults on the thermal properties of SiC are not well understood. In this study, we evaluated the accuracy of Tersoff, MEAM, and GW potentials in describing the thermal transport of SiC. Additionally, the thermal conductivity of 3C/4H-SiC nanowires was investigated using non-equilibrium molecular dynamics simulations (NEMD). Our results show that thermal conductivity exhibits an increase and then saturation as the total lengths of the 3C/4H-SiC nanowires vary from 23.9 nm to 95.6 nm, showing the size effect of molecular dynamics simulations of the thermal conductivity. There is a minimum thermal conductivity, as a function of uniform period length, of the 3C/4H-SiC nanowires. However, the thermal conductivities of nanowires weakly depend on the gradient period lengths and the ratio of 3C/4H. Additionally, the thermal conductivity of 3C/4H-SiC nanowires decreases continuously from compressive strain to tensile strain. The reduction in thermal conductivity suggests that 3C/4H-SiC nanowires have potential applications in advanced thermoelectric devices. Our study provides insights into the thermal transport properties of SiC nanowires and can guide the development of SiC-based thermoelectric materials.
碳化硅（SiC）是一种很有前景的用于热电发电的材料。热输运性质的表征对于理解其在热电装置中的应用至关重要。堆垛层错的存在源于Si-C双层的“错误”堆叠顺序，是SiC的一个普遍特征。然而，堆垛层错对SiC热性质的影响尚未得到很好的理解。在本研究中，我们评估了Tersoff、MEAM和GW势在描述SiC热输运方面的准确性。此外，使用非平衡分子动力学模拟（NEMD）研究了3C/4H-SiC纳米线的热导率。我们的结果表明，随着3C/4H-SiC纳米线的总长度从23.9 nm变化到95.6 nm，热导率呈现出先增加然后饱和的趋势，显示了热导率分子动力学模拟的尺寸效应。3C/4H-SiC纳米线存在一个作为均匀周期长度函数的最小热导率。然而，纳米线的热导率对梯度周期长度和3C/4H的比例的依赖性较弱。此外，3C/4H-SiC纳米线的热导率从压缩应变到拉伸应变持续下降。热导率的降低表明3C/4H-SiC纳米线在先进热电装置中有潜在应用。我们的研究为SiC纳米线的热输运性质提供了见解，并可指导基于SiC的热电材料的开发。
