Structure and band gap tuning of transparent (Ba_1−xSr_x)SnO₃ thin films epitaxially grown on MgO substrates

Qinzhuang Liu^1a, Bing Li¹, Jianjun Liu¹, Hong Li¹, Zhongliang Liu¹, Kai Dai¹, Guangping Zhu¹, Peng Zhang¹, Feng Chen² and Jianming Dai²

¹ School of Physics and Electronic Information, Huaibei Normal University - Huaibei 235000, PRC
² Key Laboratory of Materials Physics, Institute of Solid State Physics, and Hefei High Magnetic Field Laboratory, Chinese Academy of Science - Hefei 230031, PRC

^a qzliu@mail.ustc.edu.cn

Received: 14 March 2012
Accepted: 30 April 2012

Abstract

(Ba_1-xSr_x)SnO₃ (x=0–1) (BSSO) films were epitaxially grown on MgO substrates by pulsed laser deposition. X-ray diffraction, atomic force microcopy, and optical transmittance investigations reveal that the lattice and band structure properties of the BSSO films can be modified significantly by changing the Sr content. With increasing Sr content from 0 to 1 in films, the lattice parameters decrease from 4.123 to 4.037 Å gradually, while the optical band gaps energy increases from 3.50 to 4.27 eV linearly, which was attributed to the octahedral tilting distortion pushing up the minimum of conduction band. This large structure and band gap tuning of BSSO films are promising for desired applications in the thin-film architecture.