Electronic properties of p-GaN co-doped with Mn by thermal process: Surface studies

In this paper we report the method of the GaN:Mg electron structure modification by Mn co-doping. Manganese layers were deposited on p-GaN(0001) then subjected for thermal treatment processes in situ under ultrahigh vacuum (UHV) condition resulting in a dissolution of Mn in the subsurface layers. Surface-sensitive techniques such as X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and low energy diffraction (LEED) were employed in this experiment. Mn atoms introduced into the p-GaN show strong doping effect and no band bending at the surface. The valence band maximum is strongly shifted and located almost at the Fermi level (E-F). The Ga-3d and N-1 s peaks are shifted by 0.4 eV towards the E-F relative to the p-GaN substrate. After Mn incorporation into the p-GaN the LEED patterns revealed (1 x 1)-(0001) structure with evidence of the surface faceting.