Perovskite-type nitrogen substituted SrTiO
3 thin films were deposited with a one-step process by RF-plasma assisted pulsed laser deposition from a SrTiO
3 target using a N
2 plasma, while deposition with a NH
3 plasma yields films with almost no incorporated nitrogen. The deposited films exhibit a cubic perovskite-type crystal structure and reveal oriented growth on MgO(100) substrates. The unit cell parameters of the studied N-doped SrTiO
3 films range within 3.905<
a<3.918 Å, which is slightly larger than for SrTiO
3 (
a=3.905 Å). The nitrogen content in the deposited films varies from 0.2 to 0.7 atom%. The amount of incorporated nitrogen in the films decreases with increasing RF-power, while the N
2 flow rate does not have any pronounced influence on the N content. Nitrogen incorporation results in an increased optical absorption at 400–600 nm, which is associated with N(2
p) energy states that have a higher energy level than the valence band in strontium titanate. The optical band gap energies in the studied N-doped SrTiO
3 films are at 3.2–3.3 eV, which is very similar to that of pure strontium titanate (~3.2 eV). Films deposited with NH
3 for the RF-plasma exhibit a lower degree of crystallinity and reveal almost no nitrogen incorporation into the crystal lattice.
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