In-situ nitrided pulsed-laser-deposited SrTiO3 films

Abstract

We demonstrate in-situ nitrogen doping of archetypal ABO3 perovskite oxide, SrTiO3. In contrast to ordinary diffusion-based high-temperature nitriding, we employ pulsed laser deposition of thin films, whereto nitrogen is introduced in-situ during the growth. The nitrided polycrystalline films on commercial silicon substrates were obtained by deposition using nitrogen gas atmosphere. The nitrogen incorporation into the films was evidenced by x-ray photoelectron spectroscopy and proven by ultra-violet spectroscopic ellipsometry. By comparing the nitrided and regular films possessing similar microstructures, effects of nitrogen substitution on the optical and electrical behavior were identified. The nitrogen doping produced noticeable changes in the optical bandgap, static dielectric permittivity, and electrical conductivity. The revealed effects are critical for applications in capacitors, varactors, resistive switching, and catalysis and deserve further studies.