Vacancy-mediated effects for simultaneously enhancing the Cu/graphene/Al interfacial bonding strength and thermal conductance: a first-principles study

摘要

In the present work, the effects of vacancy in graphene on the bonding strength, electronic characteristics and thermal conductance of Cu/graphene/Al interface are deeply studied by first-principles calculation. It is found that the introduction of appropriate vacancies could simultaneously enhance the Cu/graphene/Al interfacial bonding strength and thermal conductance. The Cu(111)/perfect graphene/Al(111) interfacial bonding strength is very low because of the limited interface charge transfer. However, when the vacancy is introduced in the graphene, the Cu(111)/graphene/Al(111) interfacial bonding strength could enhance several times, the enhancement effect increases with the vacancy concentration, and the increasement of vacancy area has a better effect for the enhancement of Cu(111)/graphene/Al(111) interfacial bonding strength at the same vacancy concentration. The reason why the vacancy in graphene could significantly improve the interfacial bonding strength is that the Cu-p and Al-p state of interfacial Cu and Al atom are more delocalized and could effectively hybridize with the p states of C atom near the vacancy in graphene. In addition, the introduction of vacancy could effectively increase the phonon density of states matching degree between the interfacial Cu, Al atoms and C atoms in graphene, and thus could effectively enhance the thermal conductance across the Cu(111)/graphene/Al(111) interface.