石墨烯/碳化硅异质界面热学特性的分子动力学模拟  

Thermal property of graphene/silicon carbide heterostructure by molecular dynamics simulation

作　　者：刘东静 王韶铭[2] 杨平 Liu Dong-Jing;Wang Shao-Ming;Yang Ping(School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,China;School of Mechanical and Electrical Engineering,Guilin University of Electronic Technology,Guilin 541004,China)

机构地区：[1]江苏大学材料科学与工程学院,镇江212013 [2]桂林电子科技大学机电工程学院,桂林541004

出　　处：《物理学报》2021年第18期277-286,共10页Acta Physica Sinica

基　　金：广西自然科学基金(批准号:2018GXNSFBA281126);广西科技基地和人才专项(批准号:桂科AD18281031);中国博士后科学基金(批准号:2016M601729);广西制造系统与先进制造技术重点实验室课题(批准号:19-050-44-002Z)资助的课题.

摘　　要：为了调控石墨烯/碳化硅异质界面传热特性,采用非平衡态分子动力学方法研究温度、尺寸、材料缺陷率对界面热导的影响,通过声子态密度和声子参与率对界面热导变化的原因进行阐述分析.研究表明:两种界面作用力下界面热导均随温度升高而增大,但共价键的异质界面热导要高于范德瓦耳斯作用力下的界面热导.异质界面的界面热导随着碳化硅层数的增加而降低,当层数从10层增加到20层时,界面热导下降30.5%;4层时异质结构界面热导最低,分析认为中低频段更多的声子从局域进入离域模式.空位缺陷的引入可以有效地提高界面热导,随着碳化硅和石墨烯缺陷率的增加,界面热导均先升高再降低.300 K时当碳化硅和石墨烯缺陷率分别为20%和35%时界面热导达到最大值,分析认为缺陷的引入会阻碍中频声子的热输运.研究结果揭示可以通过尺寸效应和空位缺陷来进行异质界面的改性研究,有利于第三代半导体微纳器件的设计和热管理.In order to regulate thermal transfer characteristics of graphene/silicon carbide heterogeneous interface,the influence of temperature,size and material defect rate on thermal conductance of heterogeneous interface are studied by the non-equilibrium molecular dynamics method.The sandwich model of graphene/silicon carbide heterostructures with different lengths and thickness is built by Material Studio.The reasons for the change of thermal conductance are analyzed from the two aspects of phonon density of states and phonon participation rate.When the system temperature is below the Debye temperature of silicon carbide and graphene,the quantum corrections is used to calculate the thermal conductance of heterostructure in the paper.The results show that the thermal conductance increases with the increase of temperature under both interfacial forces,but the thermal conductance of heterogeneous interface under covalent bond is higher than under van der Waals force.The main reason is that the density of states of graphene in a range of 10—30 THz increases significantly with the increase of temperature.The thermal conductance of heterogeneous interface decreases with the increase of silicon carbide layers,and decreases by 30.5%when the number of silicon carbide layers increases from 10 to 20.The thermal conductance of heterostructure is the lowest in the thermal conductances of 4 layers,it is considered that more phonons are transferred from local to delocalized mode in the middle and low frequency band.The introduction of vacancy defects can effectively improve the interface thermal conductance.At different temperatures,the interfacial thermal conductance first increases and then decreases with the increase of graphene defects,and the defect rate when the interfacial thermal conductance reaches the maximum value and the degree of interfacial thermal conductance decrease after reaching the maximum value is related to temperature.When the defect rate of silicon carbide and graphene are 20%and 35%respectively at 300 K,t

关 键 词：异质界面 尺寸效应 空位缺陷 界面热导 

分 类 号：TB34[一般工业技术—材料科学与工程]