AUTHOR=Huang Ziheng , Ma Qiushuang , Wang Depeng , Zhao Rongjing , Niu Ruifeng , Wang Weitian 

TITLE=The band gap and nonlinear optical susceptibility of SrSn1-xVxO3 films

JOURNAL=Frontiers in Materials

VOLUME=10

YEAR=2024

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2023.1341006

DOI=10.3389/fmats.2023.1341006

ISSN=2296-8016

ABSTRACT=<p>Perovskite-type oxide SrSn<sub>1-<italic>x</italic></sub>V<sub><italic>x</italic></sub>O<sub>3</sub> thin films with different concentrations <italic>x</italic> = 0.1–0.9 were fabricated by using pulsed-laser deposition, and the effects of V doping on the structure, optical band gap and the third-order optical nonlinearity were systematically investigated. With the increase of <italic>x</italic> value, the lattice parameters of SrSn<sub>1-<italic>x</italic></sub>V<sub><italic>x</italic></sub>O<sub>3</sub> decrease from 3.997 to 3.862 Å gradually, while the optical band gaps firstly increase and then decrease with boundary at <italic>x</italic> = 0.3. The third-order nonlinear optical responses were studied via the z-scan technique. The closed-aperture measurements show a negative nonlinear refractive index <italic>n</italic><sub>2</sub>, and the open-aperture measurements demonstrate a saturable absorption <italic>β</italic>. Both the <italic>n</italic><sub>2</sub> and <italic>β</italic> responses vary with the increase of V doping level. The metal-oxygen chemical bond along with the localized V<sup>5+</sup>Sn<sup>2+</sup>V<sup>5+</sup> complex contribute to the enhancement of optical nonlinearity, and the highest value of third-order susceptibility <italic>χ</italic><sup>(3)</sup> is observed in SrSn<sub>0.5</sub>V<sub>0.5</sub>O<sub>3</sub> film.</p>