Effect of Process Parameters and Post Annealing Temperature on Structural and Optical Properties of MgTiO3 Thin Films Deposited by RF Magnetron Sputtering

Abstract

MgTiO3 (MTO) thin films have been deposited on to SiO2 substrates at ambient temperature by RF magnetron sputtering at different oxygen mixing percentage (OMP). The MTO target has been synthesized by mechanochemical synthesis method and sintered at 1,350 °C for 3 h. The phase purity of the sputtering target was confirmed from X-ray diffraction pattern and it could be refined to $$ R\bar{3} $$ space group with lattice parameters a = b = 5.0557(12) Å, c = 13.9003(9) Å. The effect of annealing on crystal structure, and optical properties of MTO thin films studied systematically. The as deposited films were X-ray amorphous irrespective of the processing parameters and exhibit refractive index in the range of 1.84–1.97 at 600 nm with an optical absorption edge value in between 3.72 and 3.78 eV. On annealing at 700 °C for 1 h, the films were polycrystalline accompanied by an increase in refractive index and band gap and decrease in transmittance. The increase in the refractive index and band gap on annealing can be attributed to the improvement in packing density and crystallinity decrease in porosity ratio.