Effects of ambient gas pressure on (1−x) SrTiO3-xBaTiO3 films prepared by pulsed laser deposition

Ambient gas pressure in pulsed laser deposition process has been observed to significantly modify the lattice parameters of (Sr1−xBax)TiO3 thin films. The lattice parameters a0 of the films deposited under low ambient pressure regime (P≤0.01 mbar) were larger than those found on the films grown under high ambient pressure regime (P≥0.1 mbar), regardless of the thin film composition (i.e., x value), substrate materials (Pt/Si or Si), or ambient gas species (O2 or N2). It is proposed from these observations that the large lattice parameters a0 of the films grown under low-pressure environment result from higher concentration of vacancies, which, in turn, are induced by the bombardment of energetic species ejected by laser beams.