Optical properties of SrTiO3 thin films deposited by radio-frequency magnetron sputtering at various substrate temperatures

Abstract

SrTiO 3 thin films were deposited on vitreous silica substrates at various substrate temperatures (300–700°C) by rf magnetron sputtering technique. The transition from amorphous phase to polycrystalline phase for the films occurred at the substrate temperatures of 300–400°C. Their optical properties were investigated by transmittance measurements. The fitting method was used to calculate the refractive index and the film thickness from the transparent region of the transmittance spectra. The refractive index increased and the film thickness decreased with the substrate temperatures increasing. The dispersion of the refractive index was studied by considering a single electronic oscillator model. The band gaps of the films were estimated from Tauc’s law and showed a decreasing tendency to that of the bulk SrTiO3 with the substrate temperatures increasing. These results provide some useful references for the potential application of SrTiO3 films in integrated optics devices.

Influence of oxygen vacancies on optical properties of anatase TiO2 thin films

“…SrTiO 3 (STO, a ¼ 0.3905 nm) substrate is also a good candidate for growth of anatase TiO 2 thin films [4]. However, because STO substrate has a band gap (3.3 eV) similar to TiO 2 (3.2 eV) [5], this substrate is inappropriate for the optical study of the films. LAO has a larger band gap (5.0 eV) [6] and good lattice matching with an a-axis length of anatase TiO 2 .…”

Nanostructure and Optical Property Investigations of SrTiO3 Films Deposited by Magnetron Sputtering

“…Chemical techniques include atomic layer deposition (ALD) [7], metal organic vapor deposition (MOCVD) [8], and the sol-gel process [9], among others. Physical techniques include pulsed laser deposition (PLD) [10] and magnetron sputtering [11,12,13], among others. Compared to other techniques, magnetron sputtering shows many advantages, i.e., wide compositional versatility, very high purity, extremely high adhesion of films, controllable deposition rate, etc.…”

Preparation and properties of ZnO:Mo thin films deposited by RF magnetron sputtering

“…For analyzing the above formula for the present case, the curve of 1/(n 2 -1) vs. 1/λ 2 has been plotted in Fig.4 Since ZnO is a direct band gap material, Tauc relation [6] of (αhν) 2 =C( hν-E g ) can be used to determine the band gap E g , where C is a constant. By extrapolating the linear portion of (αhν) 2 vs. hν plot to (αhν) 2 =0, E g of 3.46 eV was obtained, as shown in Fig.5.…”

“…The optical properties can be analyzed from the transmittance spectrum by using the fitting method [6] . In the present case, a four-phase model (air/film/substrate/air) was used.…”