Width dependence of annealing effects in (Ga,Mn)As nanowires

We study the time dependence of annealing on a series of GaAs-capped (Ga,Mn)As nanowires of varying widths. For different annealing times, our measurements indicate that decreasing the wire width monotonically increases the Curie temperature enhancement associated with annealing, as well as the drop in resistivity. These results are consistent with the lateral diffusion of interstitial Mn ions, which constitute an important source of defects in these materials. Furthermore, the thinner wires show a higher rate of change of conductivity with annealing time, suggesting a more efficient removal of Mn interstitials in thinner wires.