Optical study of Ba(Mn_xTi_(1-x)O_3) thin films by spectroscopic ellipsometry  

作　　者：张婷 殷江 丁玲红 张伟风 

机构地区：[1]National Laboratory of Solid State Microstructures, Nanjing University [2]Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University

出　　处：《Chinese Physics B》2013年第11期589-593,共5页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.60976016);the Postdoctoral Science Foundation of China(Grant No.2012M511250);the Foundation Co-established by Henan Province and the Ministry of Henan University,China(Grant No.SBGJ090503)

摘　　要：Stoichiometric Ba（MnxTi（1-x）O3） （BMT） thin films with various values of x were deposited on Si（111） substrates by the sol-gel technique. The influence of Mn content on the optical properties was studied by spectroscopic ellipsometry （SE） in the UV–Vis–NIR region. By fitting the measured ellipsometric parameter （Ψ and Δ） with a four-phase model （air/BMT＋voids/BMT/Si（111））, the key optical constants of the thin films have been obtained. It was found that the refractive index n and the extinction coefficient k increase with increasing Mn content due to the increase in the packing density. Furthermore, a strong dependence of the optical band gap Eg on Mn/Ti ratios in the deposited films was observed, and it was inferred that the energy level of conduction bands decreases with increasing Mn content.Stoichiometric Ba（MnxTi（1-x）O3） （BMT） thin films with various values of x were deposited on Si（111） substrates by the sol-gel technique. The influence of Mn content on the optical properties was studied by spectroscopic ellipsometry （SE） in the UV–Vis–NIR region. By fitting the measured ellipsometric parameter （Ψ and Δ） with a four-phase model （air/BMT＋voids/BMT/Si（111））, the key optical constants of the thin films have been obtained. It was found that the refractive index n and the extinction coefficient k increase with increasing Mn content due to the increase in the packing density. Furthermore, a strong dependence of the optical band gap Eg on Mn/Ti ratios in the deposited films was observed, and it was inferred that the energy level of conduction bands decreases with increasing Mn content.

关 键 词：Ba（MnxTi（1-x）O3） （BMT） thin films spectroscopic ellipsometry refractive index extinction co-efficient 

分 类 号：O484.41[理学—固体物理]