Electrical conductivity and p-n junction-depth measurements were used to study the diffusion of K (introduced by ion implantation) in crystals with very low O and N concentrations. At 500 to 800C, the diffusivity obeyed:

D (cm2/s) = 1.1 x 10-8 exp[-0.80(eV)/kT]

E.I.Zorin, P.V.Pavlov, D.I.Tetelbaum, A.F.Khokhlov: Fizika i Tekhnika Poluprovodnikov, 1972, 6[1], 28-33