Full range optical and electrical properties of Zn-doped SnO2 and oxide/metal/oxide multilayer thin films deposited on flexible PET substrate

As a potential replacement of indium-tin oxide (ITO), Zn-doped SnO2/Ag/Zn-doped SnO2 multilayer transparent conducting electrodes were prepared on the flexible poly ethylene terephthalate (PET) substrates by RF sputtering at room temperature. To find the optimized composition of Zn-doped SnO2 thin film, which will have higher conductivity and transmittance as compared to the undoped SnO2 thin film, an off-axis Continuous Composition Spread (CCS) sputtering method was used. Zn-doped SnO2 thin films have lower resistivity than undoped SnO2 thin films due to excess oxygen vacancies (Vo) and/or zin interstitials (Zni) in thin films. The minimum resistivity of thin film was 0.13 Ω cm at optimized 2.43 wt% Zn-doping. Zn-doped SnO2/Ag/Zn-doped SnO2 multilayer thin films were prepared using the optimized composition deposited by an on-axis RF sputter. The multilayer TCO film has the resistivity ∼5.33 × 10−5 Ω cm and the average transmittance >85% in the 550 nm wavelength region.