Science Letters:Chemically processed Nb-doped SrTiO_3 films and properties

Homogeneous, crack-free SrNbxTi1-xO3 thin films on （110） silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions were systematically investigated. Sr（OAc）2 glacial acetic acid solution, after being refluxed and reacted with tartrate, formed Sr（OAc）2（C4H6O6）2; Ti（OBu）4 formed Ti（OAc）4-x（AcAc）x. after having the ligand partially exchanged with AcAc, while Nb（OC2H5）5 formed （OAc）2Nb（AcAc） （C4H606）by exchanging of ligand in glacial acetic acid with （CH3CO）2O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNb,Ti1-xO3 cluster sol. Methyl cellulose （MCL） caused SrNbxTi1-xO3 sol to have polymeric structure and easily form films. SrNbxTi1-xO3 films with perovskite were subsequently formed after being annealed at 650-750 ℃ for 60 min in 25% N2＋75% H2 （volume ratio） atmosphere. Resistivity of the SrNb0.1 Ti0.9O3 films at room temperature was 64 μΩ·cm, a particular T2 temperature dependence of the resistivity, from 25 K up to room temperature, was observed.

钛铪酸钡薄膜的制备与形貌

溶胶-凝胶工艺在(100)Pt/Ti/SiO_2/Si基片上制备了BaHf_xTi_(1-x)O_3(x=0.005,0.01,0.02)薄膜。通过X射线衍射仪、拉曼光谱对薄膜微观结构进行了测试,采用APEX型多功能力学测试系统的3D显微镜模块和SEM对薄膜表面粗糙和厚度进行了表征。结果表明:薄膜中Hf4+进入BaTiO_3晶格中,且BaHf_xTi_(1-x)O_3具有明显的(200)取向,当x=0.005时取向度最大(1.94),晶粒尺寸最小(21.34 nm);薄膜拉曼光谱发现随Hf4+含量的增加BaHf_xTi_(1-x)O_3薄膜各光学声子模对应的拉曼振动模式峰都发生了蓝移,显示出四方相的特征谱,四方相的程度随Hf含量的增大而减弱;所有薄膜表面较平整,均方根粗糙度(RMS)在21~26 nm之间。