A study on the Raman response of TiO2 upon ion-implantation and annealing in O2 atmosphere

Abstract

The doped TiO2 materials exhibit extraordinary opto-electronic properties and in this regard, Ion-Implantation process offers extreme control and flexibility to fabricate such materials. In this work, it is shown that the electronic structure, optical absorption and raman response of TiO2 to be modified by single ion and sequential implantation process with Ag− (65 KeV), Au− (80 KeV) ions and post-implantation annealing at 450 °C for an hour in O2 atmosphere. The raman spectra of implanted and implanted/annealed TiO2 films depict anatase phase characteristics and implantation-induced effects are believed to alter the crystallinity in these materials. The sequentially implanted films Au_Ag_1 × 1016/TiO2, Au_Ag_1.5 × 1016/TiO2 depict an additional band at 65 cm−1 prior to Eg(1) band at 144.35 cm−1 and are further bettered upon annealing. The absorbance of the implanted TiO2 films is increased in the visible spectral region when compared to pristine TiO2 and are further enhanced upon annealing. The film Au_Ag_1 × 1016/TiO2 (A) exhibited optical band gap ∼2.96 eV when compared to 3.13 eV of pristine TiO2 and these materials with modified optical properties have implications for Photocatalysis, Photo-electrochemical water-splitting and Photovoltaic applications.