The self-diffusion of Ga was measured directly in isotopically controlled heterostructures. Secondary ion mass spectroscopy was used to monitor the intermixing of 69Ga and 71Ga between isotopically pure GaP epilayers which had been grown, by molecular beam epitaxy, onto GaP substrates. It was found that Ga self-diffusivity in undoped GaP could be described by:

D (cm2/s) = 2.0 x 100 exp[-4.5(eV)/kT]

at temperatures of between 1000 and 1190C, under P-rich condition. The entropy of self-diffusion was estimated to be about 4k.

Gallium Self-Diffusion in Gallium Phosphide. L.Wang, J.A.Wolk, L.Hsu, E.E.Haller, J.W.Erickson, M.Cardona, T.Ruf, J.P.Silveira, F.Briones: Applied Physics Letters, 1997, 70[14], 1831-3