Bi_(3.25)La_(0.75)Ti_3O_(12)超薄铁电薄膜的光学性质研究  

INVESTIGATIONS ON OPTICAL PROPERTIES OF VERY THIN Bi_ (3.25)La_(0.75)Ti_3O_(12) FERROELECTRIC THIN FILMS

作　　者：胡志高[1] 王根水[1] 黄志明[1] 孟祥建[1] 石富文[1] 褚君浩[1] 

机构地区：[1]中国科学院上海技术物理研究所

出　　处：《红外与毫米波学报》2003年第4期256-260,共5页Journal of Infrared and Millimeter Waves

基　　金：国家重点基础研究专项 (批准号G0 0 1CB3 0 95 )经费;国家自然科学基金项目 (批准号 60 2 2 3 0 0 6)资助项目~~

摘　　要：采用化学溶液沉积法在Pt/Ti/SiO2 /Si衬底上制备了厚度小于 10 0nm的Bi3 .2 5La0 .75Ti3 O12 (BLT)铁电薄膜 ,测量了光子能量为 2～ 4 .5eV的紫外可见椭圆偏振光谱 .根据经典的电介质光学色散关系和五相结构模型 ,拟合获得薄膜在透明区和吸收区的光学常数、表面粗糙度、薄膜与衬底界面层以及BLT薄膜的厚度 .薄膜在透明区的折射率色散关系可以通过单电子Sellmeier模型成功地进行解释 .最后 ,根据Tauc′s法则 ,得到Bi3 .2 5La0 .75Ti3 O12 薄膜的直接禁带宽度为 3.96eV .Bi3.25La0.75Ti3O12(BLT) ferroelectric thin films(<100nm) were deposited on Pt/Ti/SiO2/Si substrates using chemical solution methods. The ultraviolet-visible ellipsometric spectra of the BLT thin films have been investigated in the photon energy range of 2 similar to 4. 5 eV. Based on the classical optical functions of the dielectrics and five-phase structure model, the optical constants of the BLT thin films in the transparent and absorption region, the surface roughness, the thicknesses of the BLT thin films and the interface layer between the films and substrates were simultaneously obtained by the fitting. The dispersion of the refractive index in the transparent region fitted well to a single-term Sellmeier relation. Finally, a 3.96ev direct band gap of the Bi3.25La0.75Ti3O12 thin films was obtained employing Tauc's principle.

关 键 词：椭偏光谱 光学常数 光电材料 禁带宽度 化学溶液沉积法 铁电薄膜 光子能量 光学色散关系 表面粗糙度 

分 类 号：TN204[电子电信—物理电子学] O484.1[理学—固体物理]