脉冲激光沉积制备SrSn1-xCoxO3外延薄膜的微结构表征及能带调控

钙钛矿结构SrSnO₃因其独特的介电和半导体性质而备受关注,通过掺杂可显著调控其电学、磁学性能,拓宽其应用范围。本研究在单晶SrTiO₃(001)衬底上通过脉冲激光方法外延生长了SrSn_1-xCo_xO₃ (x = 0, 0.16, 0.33, 0.5) (SSCO)薄膜,探究了Co含量对薄膜结晶性、微观结构、光学性能以及介电性能的影响。结果表明, SrSn_1-xCo_xO₃薄膜可在SrTiO₃(001)衬底上外延生长, Co掺杂不会导致薄膜结晶质量的劣化。薄膜表面形貌平整、致密,膜厚200 nm,表面粗糙度为0.44 nm。随薄膜中Co掺杂量增加,薄膜透过率从90%降至25%,光学带隙从4.24 eV降至2.44 eV。介电性能测试表明,掺杂薄膜在10⁶Hz时介电常数为70.1,比无掺杂SrSnO₃薄膜提高57%。室温时SSCO薄膜表面电阻率为172 MΩ,在1000℃范围内薄膜结构稳定。

Microstructure and Band Gap Modulation of SrSn1-xCoxO3 Epitaxial Thin Films via Pulsed Laser Deposition

Perovskite-structured SrSnO₃ has attracted considerable attention in recent years because of its unusual dielectric and semiconducting properties. Certain dopants can be used to modify and improve the properties of these materials. Epitaxial SrSn_1-xCo_xO₃ (x = 0, 0.16, 0.33, 0.5) (SSCO) thin films were deposited on single crystal SrTiO₃(001) substrates via the pulsed laser deposition method. The crystallinity, microstructure, optical, and electrical properties of the films were investigated. The results indicated that SrSn_1-xCo_xO₃ films were epitaxially grown on SrTiO₃(001) substrate with both a perovskite structure and high crystallinity irrespective of the Co doping level. The films exhibited a smooth and dense morphology with a root-mean-square roughness of 0.44 nm and a film thickness of ~200 nm. As the'x' value increased from 0 to 0.5, the optical transmittance decreased from 90%to 25%, and the band gap dropped from 4.24 to 2.44 eV. Moreover, the doped film exhibited a high dielectric constant of 70.1 at 10⁶ Hz, 57% higher than the control SrSnO₃ film. The SSCO film displayed surface resistivity of 172 MΩ at room temperature and high stability at temperature up to 1000℃.