Annealing Effects on Resistivity Properties of Vacuum Evaporated Cu2S Thin Films

Cu2S thin films have been prepared by vacuum evaporation method from CuS powder. Cu2S was deposited onto precleaned flat glass substrates coated under a pressure of 10 torr at an evaporation rate of 3Å /sec. The resistivity of the vacuum evaporated Cu2S thin films was measured in the temperature range 303K-453K and was found between 10 to 10 ohm cm. This low resistivity is due to degenerate nature of the film. Resistivity of the films was analyzed using four probe method. Low thickness Cu2S film exhibit copper-rich phases whereas the film exhibit sulphur –rich phases towards the higher thickness. Annealing effect shows that the resistivity increases when the films are annealed at 100C and with further increase in annealing temperature, the Cu2S films shows slight decrease in resistivity. Variation in transition temperature, sheet resistance and activation energy were determined for the Cu2S films.