湿化学工艺La_xSr_(1-x)TiO_3薄膜的制备及性能表征  

Fabrication and Characterization of La_xSr_(1-x)TiO_3 Films by Sol-gel Process

作　　者：常亮亮[1] 殷明志[1] 杨亮亮[1] 

机构地区：[1]西北工业大学理学院,西安710129

出　　处：《绝缘材料》2010年第5期22-25,29,共5页Insulating Materials

摘　　要：采用湿化学工艺在硅衬底上成功地制备了结构致密、均匀且无龟裂的LaxSr1_xTiO3（LSTO）薄膜。金属硝酸盐（或氯化物）的冰醋酸溶液经回流再加入乙酸酐除去无机阴离子和结晶水,而形成的金属醋酸盐与适当的络合剂形成的多配体络合物经部分水解生成的羟基化合物M（OH）2（L）x（L=C3H5（OH）3或AcAc,M=Sr或Ti或La）,经羟基聚合形成LaxSr1_xTiO3（LSTO）簇状溶胶。丙三醇抑制了羟基金属过度羟基聚合,甲基纤维素（MCL）使LSTO溶胶具有网状结构。LSTO凝胶薄膜经过575~725℃/60min退火形成立方钙钛矿结构。用XRD、SEM对薄膜结构和形貌表征。室温下LSTO薄膜的电阻率为54μΩ.cm,而在160K到室温之间薄膜电阻率随温度的变化遵从ρ=ρ0＋AT2。分析结果表明：La3＋离子的施主掺杂实现了SrTiO3的n-型半导体化。Homogeneous,crack-free LaxSr1-xTiO3（LSTO） films on/SiO2/silicon（110） substrates were successfully fabricated by sol-gel processing.The optimum route and conditions were systematically investigated.Sr（OAc）2 glacial acetic acid solution was reacted with C3H5（OH）3,to form Sr（OAc）2（C3H5（OH）3）x;Ti（OBu）4 molecule was partially exchanged with AcAc to form Ti（OAc）2（AcAc）2;while La（NO3）3·6H2O needs being changed into La（AcAc）2（OAc）2 by ligand exchange in glacial acetic acid under anhydrous medium conditions.All the species were partially hydrolyzed and polymerized by hydroxyl or oxygen to form LSTO polymeric sol.Methyl cellulose（MCL） can make the LSTO sol with network polymeric structure and filming.LSTO films with cubic perovskite structure were subsequently obtained after annealing at 575～725 ℃ for 60 min.XRD and SEM were employed for structure and morphology characterization.The resistivity of the LSTO films at room temperature is 54 μΩ·cm;a particularly striking T2 temperature dependence of the resistivity,from 160 K up to room temperature,was observed.The results thus strongly suggest that doped La3＋ can modify the width of the valence band l ℃ ated between the upper part of forbidden band and the bottom of conducting band;and change SrTiO3 into n-type semi-conductivity.

关 键 词：SrTiO3施主掺杂 LaxSr1_xTiO3薄膜 半导化 

分 类 号：TM215.3[一般工业技术—材料科学与工程] TM206[电气工程—电工理论与新技术]