Improvement of the conductivity and transmittance of AZO/Ag/AZO composite film via lattice oxygen ratio regulation

Abstract High conductivity and high transmittance are usually contradictory for transparent conductive films. AZO/Ag/AZO composite film was deposited with magnetron sputtering on K9 glass substrate at room temperature, and O2 was used as the reactive gas to control the ratio of lattice oxygen and that of oxygen vacancy in the bottom AZO layer, which regulated the composite film's conductivity and transmittance. The results showed that the lattice oxygen ratio of the bottom AZO layer first increased and then decreased as the O2 flow ratio increased from 0% to 30%, while the oxygen vacancy ratio decreased continuously; both the in-plane stress in the AZO layer and the lattice mismatch between AZO and Ag layers first decreased and then increased. The crystallization quality of the Ag layer increased first and then decreased and got the best at 10% O2 flow ratio, while the roughness first decreased and then increased, and got the minimum value at 10% O2 flow ratio. As the O2 flow ratio increased from 0% to 30%, the transmittance of the AZO/Ag/AZO composite film first increased and then decreased, while the sheet resistance first decreased and then increased; when the O2 flow ratio was 10%, the average visible transmittance (380–780 nm) of the composite film got the maximum 78.28%, the sheet resistance got the minimum 6.745 Ω/sq.