Monte Carlo simulation for temperature dependence of Ga diffusion length on GaAs(0 0 1)

Diffusion length of Ga on the GaAs(0 0 1)-(2 × 4)β2 is investigated by a newly developed Monte Carlo-based computational method. The new computational method incorporates chemical potential of Ga in the vapor phase and Ga migration potential on the reconstructed surface obtained by ab initio calculations; therefore we can investigate the adsorption, diffusion and desorption kinetics of adsorbate atoms on the surface. The calculated results imply that Ga diffusion length before desorption decreases exponentially with temperature because Ga surface lifetime decreases exponentially. Furthermore, Ga diffusion length L along [1 1̄ 0] and [1 1 0] on the GaAs(0 0 1)-(2 × 4)β2 are estimated to be L_{[1 1̄ 0]} ≅ 700 nm and L_{[1 1 0]} ≅ 200 nm, respectively, at the incorporation-desorption transition temperature (T ∼ 860 K).