Effects of Gas Pressure and Discharge Power on Electrical and Optical Properties of Zno:al Thin Film Deposited on Polymer Substrate

In this paper aluminium-doped zinc oxide(ZnO:Al) conducting layer was deposited on polyethylene terephthalate(PET) substrate by r. f. magnetron sputtering method. The effects of gas pressure and r. f. sputtering power on the structural and electrical properties of ZnO:Al thin film were investigated experimentally. The results show that the resistivity of the film was strongly influenced by the gas pressure and r. f. sputtering power. The electrical properties were improved with increase in sputtering power and gas pressure up to 180W and 5mTorr. However excessive supply of sputtering power limits the growth of crystalline grains due to too high deposition rate and may cause a degradation of the preferred orientation, giving high electrical resistivity. The lowest resistivity and optical transmittance were ~1.1×10�-cm and ~85%, respectively and were obtained under the experimental conditions of 180W of sputtering power and 5mTorr of gas pressure.