The diffusion of Na into Cl-doped material, from the vapor phase, was studied at 470 to 970K. The diffusivity was determined by means of layer stripping and Hall effect measurements. It was found that the results depended upon the hole concentration of the samples used. The data could be described by:

D (cm2/s) = 1.18 x 10-6 exp[-0.25(eV)/kT]

when the hole concentration was between 109 and 1010/cm3, by:

D (cm2/s) = 8.97 x 10-5 exp[-0.62(eV)/kT]

when the hole concentration was between 1011 and 1012/cm3. The effect of the holes was explained in terms of vacancy diffusion mechanisms. It was concluded that Na diffusion occurred via a dissociative mechanism, and that the solubility and activation energy of Na were governed by the degree of doping. A vacancy diffusion mechanism predominated in Cl-doped material when the Cl content was at the intrinsic impurity level of about 1016/cm3.

J.M.Ivanov, G.S.Pavlova, E.L.Kanunova: Izvestiya Akademii Nauk SSSR - Neorganicheskie Materialy, 1988, 24[12], 1959-62. (Inorganic Materials, 1989, 24[12], 1681-4)

The best linear fits to the solute diffusion data ([26] to [45]) yield:

Cu: Ln[Do] = 0.21E – 14.3 (R2 = 0.06); Hg: Ln[Do] = E – 38.8 (R2 = 0.98);

In: Ln[Do] = 0.40E – 16.9 (R2 = 0.91); Na: Ln[Do] = 0.67E – 18.1 (R2 = 0.99)