Influence of the ZnO:Al dispersion on the performance of ZnO:Al/Ag/ZnO:Al transparent electrodes

Highly transparent and conductive Al-doped ZnO/Ag/Al-doped ZnO (AZO/Ag/AZO) multilayers were prepared by industrial inline DC magnetron sputtering on glass substrates at room temperature. With optimized film thicknesses of 37 nm/10 nm/37 nm, an optimized low sheet resistance of only 6 Ω/sq. and high transmittances of T550 = 87.4% at 550 nm and T400-800 = 79.9% in the spectral range between 400 nm and 800 nm were reached. Furthermore, an increase of the AZO/Ag/AZO-performance was achieved when a small amount of oxygen was added to the process gas during the AZO deposition which was found to be because of a beneficial adjustment of the AZO dispersion. In this way, owing to both a decreased extinction coefficient as well as a higher refractive index of the AZO film, the maximum transmittance of the AZO/Ag/AZO three-layer structure is further increased (T550 = 89.0%) and the bandwidth of the transmittance range is broadened (T400-800 = 83.3%). With the adaption of the AZO dispersion a very high Figure-of-Merit (Haacke) Φ400-800 = 26.2 mΩ− 1 and Φ550 = 52.9 mΩ− 1 was achieved by industrial inline DC magnetron sputtering process.