First principles study of adsorption of multilayer gold atoms on graphene doped with B under various concentrations

The high contact resistance between graphene and metal retards the application of graphene in micro-and nano-electronics. Boron (B) doping can effectively reduce the contact resistance of graphene. The influence of dopant concentration on the adsorption of multilayer gold (Au) atoms on B-doped graphene was studied using the first principles theory. Firstly, the binding energy of B-doped graphene with various B concentrations was calculated, and the stability of each B-doped graphene was verified. Then, after structural optimization of B-doped graphene, multilayer Au atoms were introduced into graphene and the adsorption energy, pseudogap, local density of state, charge density distribution, and charge transfer of the adsorption system were analyzed. The B concentrations considered were respectively 1.39%,4.17%,6.94%,9.72%,12.50% and 15.28%. The results show that as B concentration increases, the pseudogap of the adsorption system becomes wider and the adsorption energy rises, leading to a more stable adsorption system. Also, an obvious hybridization between B and Au atoms takes place. This elevates the charge density and promotes the charge transfer at the interface of graphene and Au, which can help reduce the contact resistance between them. However, when the concentration reaches 15.28%, the geometric deformation of graphene becomes intolerable due to a high doping concentration.