Growth and characterization of Mn-doped cubic-GaN

We report on the growth and characterization of Mn-doped cubic-GaN films. The n-type carriers, which are resulting from the formation of nitrogen vacancies, were intentionally utilized. For a 3% Mn sample with a high carrier density (similar to 1 x 10(20) cm(-3)), we found substitutional Mn atoms on both the Ga-site and N-site, i.e., (Ga,Mn)N and Ga(N,Mn) exist together. A ferromagnetic behavior was observed in this sample at low temperature (similar to 5 K), although a 3% Mn semi-insulating sample in which Mn atoms substitute only the Ga-sites in the cubic-GaN lattice showed paramagnetism even at low temperature. The structural and magnetic properties of the relatively high Mn composition (>= 5%) samples were found to be governed by precipitate clusters of antiferromagnetic GaMn3N and ferromagnetic Mn4N. (c) 2006 Elsevier B.V. All rights reserved.