A study on structural, optical and hydrophobic properties of oblique angle sputter deposited HfO2 films

HfO2 thin films have been synthesized by oblique angle reactive DC magnetron sputtering technique. Present study reports the effect of deposition angle on the hydrophobic, structural, surface morphological and optical properties of HfO2 thin films. All the films were deposited at room temperature. HfO2 thin films were found to possess monoclinic crystal structure. Significant changes in topography of the films, with change in deposition angle, have been observed. Surface roughness increases with decrease in deposition angle as observed from AFM image analysis. UV–vis spectroscopy has been used to study the optical properties of the films. Small changes in transmission and refractive index have been observed. The films are hydrophobic in nature and the contact angle is strongly influenced by deposition angle due to change in its surface roughness. Contact angle of 106.3° has been achieved for deposition angle of 30° which is highest so far for HfO2 thin films prepared by magnetron sputtering. The results of this study reflect that contact angle of the films can be tuned by deposition angle. Good optical transmission along with hydrophobic character make HfO2 thin films of great use as optical coatings for lenses, windshields and optoelectronic devices.