By using electron spectroscopy to monitor the spreading of thin layers of Au on GaAs at 240 to 420C, it was found that the diffusivity could be described by:

D (cm2/s) = 4.5 x 10-8 exp[-20(kcal/mol)/RT]

R.P.Gupta, W.S.Khokle, J.Wuerfl, H.L.Hartnagel: Thin Solid Films, 1987, 151[3], L121-5

Figure 4

Diffusivity of Fe in Au

(Circles: 5GPa H2, square: 5GPa, no H2)