不同类型缺陷对多层石墨烯热导率的影响

The Effect of Defect Type on the Thermal Conductivity of Multi-layer Graphene

本文采用分子动力学方法研究了300 K,650 K和1400 K温度下,片层尺寸8.70×7.48 nm2的12层石墨烯在一定数量的空位缺陷、杂质N原子和杂质化学官能团-CH3影响下的热导率。采用频谱能量密度分析方法求解了声子色散关系。结果发现杂质N原子掺杂仅影响了材料内原子质量和键长键角,对热导率影响较小;而-CH_3官能团引入了额外的官能团平动和转动能量,对热导率有一定影响;空位缺陷不仅影响了声子传递,还额外激发了高频声子,对热导率影响最大。

This work employs molecular dynamics method to investigate the thermal conductivities of multi-layer graphene with vacancy, N-doping and-CH_3 group at 300 K, 650 K and 1400 K, whose size is 8.70 x7.48 nm2 with 12 layers. The spectral energy density（SED） analysis is adopted to solve the phonon dispersion relation of the graphene. It is found that N-doping just slightly affect the thermal conductivity due to the minor excursions of atom masses and bond energy caused by the doping. The-CH3 group in the multi-layer graphene can introduce extra translational kinetic energy as well as rotational kinetic energy, so that it can remarkably affect the thermal conductivity. For the vacancy, it can not only introduce extra energy, but also excite extra high-frequency phonon. Hence the effect of vacancy on thermal conductivity is the most remarkable.