First-Principles Study of Ag-Doped GaAs Nanowires

The structural and electronic properties of undoped and Ag-doped unpassivated wurtzite GaAs nanowires (NWs), as well as their stability, are investigated within the first-principles frame. The calculated formation energies show that the single Ag energetically prefers to substitute the surface Ga (Ef = −0.529 eV) under As-rich conditions, and creates a much shallower (0.19 eV above the Fermi) acceptor level, which is of typical p-type character. With the increase in the Ag concentration, the p-type behavior gradually weakens and the n-type character arises. Thus, one can expect to synthesize Ag-doped GaAs NWs for p-type or n-type applications by controlling their Ag concentration and microarrangement.