Transition metal diffusion in diluted magnetic Si and GaAs prepared by pulsed laser processing

Starting from a random or ordered distribution of 0.8%, 1.6%, 3.7%, and 12.5% dopants over the lattice sites of a simple cubic grid, we estimate the fraction of unclustered dopants after pulsed laser processing of different host:dopant systems. Initial clustering events are simulated with a greedy algorithm implemented in a Monte Carlo study. The greedy algorithm gives adequate results for dopants with low diffusivity and low solubility. The absolute initial dopant concentration and declustering strongly influence the kinetics of clustering. Particularly, we consider transition metal doped Si and GaAs after pulsed laser annealing, which are of interest for spintronics applications. An uncritical integral diffusion of Mn in GaAs:Mn and a tendency of Mn to form silicides in Si:Mn are simulated. These results are in good agreement with experimental observations.