The diffusion of 68Ge in single-crystal specimens of 4N-purity material was studied by using sectioning techniques. It was found that the Arrhenius plot was straight at 939 to 1675K, and was of the form:

D (cm2/s) = 2.10 x 100 exp[-2.47(eV)/kT]

S.Mantl, S.J.Rothman, L.J.Nowicki, J.L.Lerner: Journal of Physics F, 1983, 13[7], 1441-8