Structural, optical, and morphological changes in the Au ion-implanted TiO 2 thin films

The present study investigates the impact of 80 keV Au ion implantation on the physical properties of TiO 2 thin films. These films were deposited via RF sputtering, and implanted with ion fluence ranging from 5E14 to 1E16 ions cm −2 . X-ray diffraction analysis reveals that the films exhibit a polycrystalline structure, with a crystallite size of 12 nm that decreases to 9 nm at higher fluences. The diffraction peaks corresponding to the (101), (004), (105), and (204) planes confirm the TiO 2 anatase phase. Significantly, the high fluence results in increased dislocation density, suggesting the creation of defects and recrystallization. Moreover, the intensity of diffraction peaks demonstrates an improvement in crystallinity with ion implantation. Atomic force microscopy analysis was employed to determine the surface properties of the films, including surface topology, root mean square (RMS) roughness, grain height, and average size. The films exhibit smoother surfaces at higher fluences compared to the pristine film. Additionally, the bandgap of the films decreases from 3.23 to 3.14 eV with increasing ion fluences. Transmittance measurements also reveal a decrease from 63 to 37% at higher fluences. Rutherford backscattering spectrometry, combined with RUMP simulation, was utilized to analyze the thickness and concentration of Au ions within the deposited thin films. The results indicated a reduction in thickness at high fluences. This study shows that Au ion implantation at lower fluence effectively modifies the material properties of TiO 2 thin films, making them suitable for applications such as electrodes in sensing, antibacterial, and solar energy devices.