AZO work function enhanced by oxygen plasma immersion ion implantation

Abstract

The surface of aluminum-doped ZnO (AZO) films was modified using the oxygen plasma immersion ion implantation method, which is also called O-PIII. The modified AZO films were analyzed by an X-ray photoelectron spectroscopy system (XPS), X-ray diffraction (XRD), a UV–visible spectrophotometer, atomic force microscopy (AFM), and a Kelvin probe instrument (KP). The results showed that O-PIII modification can further enhance the work function (WF) of AZO based on oxygen plasma (O-ICP) treatment. The optical characteristics of AZO thin films are nearly entirely preserved, and the surface morphology is enhanced. The variation in WF was strongly linked to the surface stoichiometry. The reduction of oxygen vacancies should be attributed to the high WF. The WF of the modified AZO films decreased rapidly with exposure time in the air promptly following O-ICP and O-PIII modification. Nonetheless, the O-PIII treatment had a longer-lasting effect.