The Transmittance Modulation of ZnO/Ag/ZnO Flexible Transparent Electrodes Fabricated by Magnetron Sputtering

In this study, the critical role of the oxide thickness at the top and bottom layers of the ZnO/Ag/ZnO flexible transparent conductive electrodes was investigated. The peak transmittance of an 8 nm thick Ag electrode was observed at a wavelength of 320 nm, while the addition of the top and bottom ZnO layers, which serve as antireflection coating, resulted in peak shifts to the visible light wavelengths with a simultaneous improvement in the transmittance as well as the spectral uniformity. By independently varying the thickness values of the top and bottom ZnO layers, it was determined that the thickness variation of the top ZnO layer had a dominant effect in the transmittance, while a lesser but still significant contribution was obtained by varying the thickness of the bottom ZnO layer. At the optimized values of thickness for the top and bottom ZnO layers, the ZnO/Ag/ZnO electrode exhibits peak and average transmittance of 97.2% and 89.7%, respectively, along with a sheet resistance of 7.8 Ω/sq, with a corresponding Haacke's figure of merit (ΦH = T10ave/Rs) of 0.043, which exceeds that of the conventional indium-tin-oxide electrodes.