Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Republic of Korea.
Sci Rep. 2016 Oct 4;6:34428. doi: 10.1038/srep34428.
Thermal energy transport across the interfaces of physically and chemically modified graphene with two metals, Al and Cu, was investigated by measuring thermal conductance using the time-domain thermoreflectance method. Graphene was processed using a He ion-beam with a Gaussian distribution or by exposure to ultraviolet/O, which generates structural or chemical disorder, respectively. Hereby, we could monitor changes in the thermal conductance in response to varying degrees of disorder. We find that the measured conductance increases as the density of the physical disorder increases, but undergoes an abrupt modulation with increasing degrees of chemical modification, which decreases at first and then increases considerably. Moreover, we find that the conductance varies inverse proportionally to the average distance between the structural defects in the graphene, implying a strong in-plane influence of phonon kinetics on interfacial heat flow. We attribute the bimodal results to an interplay between the distinct effects on graphene's vibrational modes exerted by graphene modification and by the scattering of modes.
采用时域热反射法测量热导，研究了物理和化学修饰的石墨烯与两种金属（Al 和 Cu）界面的热能传递。通过 He 离子束的高斯分布或暴露于紫外线/O 来处理石墨烯，分别产生结构或化学无序。通过这种方式，我们可以监测热导随无序程度变化的变化。我们发现，随着物理无序密度的增加，测量得到的电导增加，但随着化学修饰程度的增加，电导会发生突然调制，先减小然后显著增加。此外，我们发现电导与石墨烯中结构缺陷的平均间距成反比变化，这表明声子动力学对界面热流具有强烈的面内影响。我们将双峰结果归因于石墨烯修饰和模式散射对石墨烯振动模式的不同影响之间的相互作用。
