Optoelectronic properties of AZO/ZnO bilayer

Abstract

The series of ZnO thin films (such as pure ZnO, Al doped ZnO, and AZO/ZnO bilayer) were deposited on p-Si(100) substrates by RF magnetron sputtering technique respectively, which were investigated by numerical simulation and experiments from two aspects to study its interfacial and photoelectric properties. It’s found that the interface properties of Si-based films are affected remarkably by annealing process, and the AZO/ZnO bilayer has poor optical properties. According to the prepared films, 2 × 2 × 2 ZnO supercell, 2 × 2 × 2Al0·0625Zn0·9375O, Al0·0625Zn0·9375O/ZnO interface, and Al0·125Zn.0.875O/ZnO bilayer were constructed and analyzed based on first principles. Compared with other cases, the TDOS reveal that valence band of AZO/ZnO bilayer from −20eV to −17eV becomes wide, but the conduction band narrows considerably. The dielectric function of AZO/ZnO bilayer slightly moves to the lower energy directions (red shift), and its conductivity is much lower in the range of 7eV–35eV. Moreover, there is little difference between AZO/ZnO and AZO/ZnO bilayer in electrical and optical properties. It can be inferred that AZO/ZnO bilayer has adverse impact on the solar cells and other optoelectronic devices, which may supply some theoretical value for studying ZnO based optoelectronics.