Effects of O2 flux on structure, optical properties and hydrophobicity of highly emissive antireflective HfO2 thin films by magnetron sputtering

Abstract

We used magnetron sputtering to prepare high emissive HfO2 thin films with thickness 300–500 nm under different O2 flux. A dense uniform HfO2 thin film with a polycrystalline monoclinic structure had been achieved. The effects of O2 flux on structural, optical and mechanical properties of deposited thin films were investigated. With the increasing O2 flux, the thickness of both the thin film and HfSixOy interlayer found at the interface of HfO2 and Si substrate decreased while the grain size and surface roughness increased significantly. At an O2 flux of 30 sccm, the deposited HfO2 film achieved a high transmittance up to 93%, a high emissivity up to 90%, a low bandgap (5.65 eV), a high refractive index (2.03) and a good hydrophobicity with an optimum contact angle of 117.8°. The obtained results of high emissivity, optical transmission and hydrophobic behavior are best among the reported performance, with the implication for application in high-performance optical coatings of lenses, windshields and optoelectronic devices.