Here, ZnS thin films were deposited, by spray pyrolysis, onto glass substrates. The diffusion of Ag in ZnS thin films was performed at 80 to 400C under a N atmosphere. The diffusion of Ag was determined using XRF, and the obtained concentration profile permitted the calculation of the diffusion coefficient. The temperature dependence of the Ag diffusion coefficient was described by:

D cm2/s) = 8 x 10−9 exp[−0.10(eV)/kT]

It was found that the as-grown undoped highly resistive n-type ZnS thin films were converted into p-type upon Ag doping, with a slight increase in resistivity occurring only upon rapid thermal annealing at 400C in a N2 atmosphere. In addition, the band-gap of the p-type film was decreased as compared with undoped samples annealed under the same conditions. The results were attributed to the migration of Ag atoms in polycrystalline ZnS films both along intergrain surfaces and via an intragrain route, accompanied by interactions with native point defects.

Ag Diffusion in ZnS Thin Films Prepared by Spray Pyrolysis. E.Bacaksiz, O.Görür, M.Tomakin, E.Yanmaz, M.Altunbaş: Materials Letters, 2007, 61[30], 5239-42