Adsorción e incorporación de Cu en la superficie GaN(0001)

Abstract

In this work we report first principles calculations to analyze the copper adsorption and incorporation on GaN (0001) surface, and on the deeper layers of a GaN slab in a 2$\times$2 geometry. The calculations were performed using the plane-wave pseudopotential method within the framework of the density functional theory (DFT). In the description of the electron-electron interaction is used generalized gradient approximation (GGA). To study the most favorable Cu adsorption model we considered T1, T4, H3 and Br special sites. We find that the most energetically favorable structure corresponds to the 1Cu-H3 model, while the Cu adsorption on top of a Ga atom (T1 position) is totally unfavorable. Furthermore, in the Cu incorporation on the deeper layers of the studied slab, we found that these impurities prefer substitutional sites of Ga in the upper bilayers of slab, indicating that they are unlikely to Cu migrate into the volume of GaN. Finally is analyzed the density of states with and without ad-atoms of Cu.