Structures and optical properties of indium doped SrTiO_3 thin films by oxygen plasma-assisted pulsed laser deposition

摘要

Undoped and In-doped SrIn_xTi_(1-x)O_3(x=0, 0.1, 0.2) films have been deposited on Si(100) and quartz substrates by oxygen plasma-assisted pulsed laser deposition (PLD). Effects of indium doping on the crystallinity and the optical energy band gap of SrTiO_3 (STO) films were investigated. Results indicate that undoped STO film is of rather good crystallinity and low defects concentration. However indium doping deteriorates the crystallinity of the STO firm, and results in the roughening of the film surface. Moreover the a-axis length monotonically increases when increasing In content. For all the films, the average transmission in the visible wavelength region (λ=400-800nm) is over 75%. The optical energy band gap of STO thin films, measured from transmittance spectra, changes from 3.67eV to 3.93eV by indium doping.