High optoelectronic performance of ZnO films co-doped with ternary functional elements of F, Al and Mg

Abstract

For use as front electrodes in high-efficiency thin-film solar cells, ZnO transparent conductive films must have both broad spectral transmission and high conductivity. However, these characteristics are difficult to achieve simultaneously. In this work, F, Al, and Mg co-doped ZnO (FAMZO) films with superior electrical and optical properties were fabricated by RF magnetron sputtering and rapid thermal annealing (RTA). F and Al co-doping enables the film to maintain low resistivity and high transmittance in the visible and near-infrared regions, while Mg doping widens the optical band gap. Morphological characterization shows that the FAMZO films undergo recrystallization and growth during RTA, which further improves their electrical and optical properties. Our FAMZO films achieved a resistivity of 4.07 × 10−4 Ω cm, a mobility of 47.85 cm2/V, a carrier concentration of 3.21 × 1020 cm−3, and 90.54% average transmittance between 400 and 1400 nm. The excellent performance of our ZnO films makes them suitable for a broad range of applications in high-efficiency thin-film solar cells.