MnGa and (Mn,Ga)N-like alloy formation during annealing of Mn/GaN(0001) interface

Abstract

In this paper the behaviour of the Mn/GaN system under the influence of annealing is presented. The interface is formed by Mn vapour deposition onto the GaN crystal, (0001)-oriented, non-doped under ultrahigh vacuum. Physicochemical properties and structural changes of the interface induced by annealing are investigated in situ by employing X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and low-energy electron diffraction (LEED). The impact of annealing on the subsurface layer morphology is observed. Annealing effects, which have been confirmed by XPS and UPS, demonstrate Ga diffusion into the Mn film and Mn dissolution in the bulk GaN. LEED patterns confirm MnGa alloy formation, which in the plane parallel to the substrate surface is arranged in a square lattice with lattice constant equal to about 3.9 Å, and exists in epitaxial configuration relative to the substrate. Incorporation of Mn atoms into the GaN lattice results in the creation of (Mn,Ga)N-like alloy.