Isotopically controlled heterostructures were used to study Ga self-diffusion by using secondary-ion mass spectrometry. This approach produced a near-ideal random walk situation that was free of perturbations arising from electric fields, mechanical stresses, or chemical potentials. It was found that the Ga self-diffusion coefficient in intrinsic material (table 16) could be described by:

D(cm2/s) = 43 exp[-4.24(eV)/kT]

over 6 orders of magnitude, at temperatures of between 800 and 1225C, under As-rich conditions. No significant doping effects were observed in samples with substrates that were doped with Te up to 4 x 1017/cm3 or with Zn up to 1019/cm3.

L.Wang, L.Hsu, E.E.Haller, J.W.Erickson, A.Fischer, K.Eberl, M.Cardona: Physical Review Letters, 1996, 76[13], 2342-5

Table 16

Diffusivity of Ga in GaAs