Self-consistent charge-density functional tight-binding calculations were used to determine the potential energy surface for a single interstitial C atom. The results suggested a model, for the diffusion of C, which involved an activation energy of less than 1eV. The C atom moved via split-interstitial and bond-centered configurations. The energetics of the model reaction were then refined by using a fully self-consistent density-functional method. These calculations were in good agreement with the more approximate results above. Experimental studies also indicated an activation energy of about 1eV for C migration in heavily doped material.

Density-Functional Calculations of Carbon Diffusion in GaAs C.D.Latham, M.Haugk, R.Jones, T.Frauenheim, P.R.Briddon: Physical Review B, 1999, 60[22], 15117-22