Electrical conductivity of PbTe thin films

PbTe thin films were prepared by vacuum technique with different thicknesses ranging from 550 to 3000 Å. The electrical resistivity as a function of the film thickness and mobility was measured. The dependence of log (resistivity) and log (current) was studied as a function of the universal temperature. The activation energies were estimated before and after the break. The transition of conductivity from n-type to p-type is attributable to the increase in the number of migrating lead vacancies. An increase of the applied voltages on the thin films caused the shift of breaking temperature to higher temperatures. This shift is attributed to the creation of Pb vacancies which retard the break.