Optical properties of p-type In-doped SrTiO3 thin films

We report the optical properties of p-type SrInxTi1−xO3 (x=0.1 and 0.2) films prepared by laser molecular beam epitaxy under different oxygen pressures. The results of x-ray diffraction and near-field scanning optical microscopy indicate that the films have high crystallinity, smoothness, and uniformity. Hall measurement confirms that the films are p-type semiconductors. The optical transmittance spectra reveal that the films are highly transparent in most of the visible region. A blueshift of the absorption edge with an increase in oxygen pressure during deposition has been observed and discussed. Moreover, the first-order Raman scattering peaks of the optical phonons in these In-doped SrTiO3 films are presented, and they are Raman inactive in bulk SrTiO3 single crystal.