Studies on the electrical conduction in silver telluride thin films

The temperature dependence of the electrical resistance of unannealed and annealed silver telluride thin films of different thickness between 30 and 110 nm, prepared by thermal evaporation at a pressure of 2 × 10–5 mbar, has been studied. The films are polycrystalline. It is found that metastable defects influence the phase transition in unannealed films. The annealed films undergo a structural phase transition at around 410 K during heating and at around 380 K during cooling. Similar hysteresis has also been observed in the phase transition of bulk material in differential scanning calorimetry studies. It is found that the resistivity of silver telluride thin films decreases with decrease in film thickness. This may be due to the generation of free carriers by the increase of Frenkel defects due to silver atoms.