通过透射光谱研究了锰掺杂量对钛酸锶铅铁电薄膜光学特性尤其是带-带跃迁和带尾吸收特性的影响,并利用柯西色散关系获得了光学透明区的光学常数.研究表明: 随着锰掺杂量的增加,钛酸锶铅铁电薄膜的禁带宽度减小而带尾能增加.禁带宽度随锰掺杂的收缩可以归因为锰 3d轨道降低了导带底的能级及掺杂后晶格的减小.掺杂锰离子的随机占位和非等价掺杂后氧空位浓度的增加则是导致局域带尾态拓宽的主要原因.

Mn composition dependence of optical properties,especially interband electronic transition and bandtail absorption behaviors,in Mn doped(Pb,Sr) TiO3(PST)films were investigated by transmittance spectrosco. py. The optical parameters of Mn doped PST films in transparent region were evaluated by Cauchy model. The decrease of optical band gap and the expansion of the band tail states with the increasing of Mn dopant amount were observed. The shrinkage of optical band gap is attributed to lowering the bottom of conduction bands by Mn 3d orbitals and the decrease of lattice constant in Mn doped PST films.Meanwhile,the random occupation of Mn ion and the increase of oxygen vacancy after Mn doping are the main causes for the expansion of localized states in band tails.