The pure migration of individual Ga atoms on the (001)-(2 x 4) reconstructed surface was studied as a function of the substrate temperature by using a combination of molecular beam epitaxy and scanning tunnelling microscopy. One tenth of a plane of Ga atoms was successfully deposited onto a pristine surface under a constant As4 beam equivalent pressure of 10-6Torr, using various substrate temperatures. After deposition, the substrate was quenched to room temperature and observed using scanning tunnelling microscopy. A plot of the number density of islands formed, as a function of the deposition temperature, was found to obey an Arrhenius relationship. Upon assuming a pure one-dimensional diffusion model, or a pure isotropic 2-dimensional diffusion model, the activation energy for diffusion was deduced to be 2.3 or 1.7eV, respectively.

Activation Energy for Ga Diffusion on the GaAs(001)-(2 x 4) Surface H.Yang, V.P.LaBella, D.W.Bullock, Z.Ding, J.B.Smathers, P.M.Thibado: Journal of Crystal Growth, 1999, 201-202, 88-92