Formation of TiO2 nanorods by Zn and Ti ion sequential implantation with enhanced visible optical absorption properties

• Zn and Ti ions are sequentially implanted into SiO2 substrate.
• TiO2 nanorods are formed for the first time by sequential ion implantation.
• Band gap of TiO2 is reduced from 3.0 eV to about 2.5 eV.

TiO2 nanorods were fabricated by sequentially implanted with Zn and Ti ions into SiO2 substrate with post annealing in oxygen atmosphere at 1000 °C. Comparing with single Ti ion implanted sample, the absorption edge of TiO2 nanorods showed a large red shift from 375 nm to 450 nm with its optical band gap reduced to about 2.5 eV for Zn and Ti ions sequentially implanted samples. Microstructure analysis revealed that Zn was incorporated into TiO2 lattices which resulted in the band gap reduction. The results suggest that Zn and Ti ion sequential implantation is an effective way to synthesize TiO2 nanorods with enhanced visible light absorption.