LaNiO3缓冲层厚度对Ca0.4Sr0.6Bi4Ti4O15薄膜结构和电性能的影响

利用溶胶–凝胶法在Si（100）衬底上制备了具有（110）取向的LaNiO3薄膜,然后在LaNiO3/Si（100）上制备了Ca0.4Sr0.6Bi4Ti4O15（Ca0.4Sr0.6BTi）薄膜。研究了LaNiO3缓冲层厚度对Ca0.4Sr0.6BTi薄膜结构和电性能的影响。结果表明,当引入LaNiO3厚度为250 ...     

锆钛酸钡钙的结构与铁电光学性能研究

通过溶胶凝胶法,在Pt/TiO2/SiO2/Si衬底和ITO导电玻璃衬底上分别制备了BaTiO3(BTO)、(Ba0.85Ca0.15)TiO3(BCT)、Ba(Ti0.8Zr0.2)O3(BZT)和(Ba0.85Ca0.15)(Ti0.8Zr0.2)O3(BCZT)薄膜.X射线衍射结果表示,Ca、Zr元素成功掺入钛酸钡薄膜,并且造成了衍射峰的移动,对薄膜的铁电性能有较大的提升.同时用积分球光谱仪测试了薄膜的吸收光谱,通过计算得到薄膜的禁带宽度.结果 表明锆钛酸钡钙薄膜具有较小的光学带隙为3.1 eV.     

厚度对溶胶-凝胶法制备BaTi0.99Fe0.01O3薄膜的结构及电性能研究

采用溶胶-凝胶法制备在Pt/Ti/SiO₂/(100)Si基片上不同厚度的BaTi_0.99Fe_0.01O₃(BFTO)薄膜，研究了不同薄膜厚度对BFTO薄膜的晶体结构、介电和铁电性能的影响。在薄膜厚度低于370 nm时，BFTO薄膜呈现四方相结构，而随着厚度进一步增加，薄膜的四方性降低。随着厚度的增加，有利于提高薄膜的介电常数，而铁电性能逐渐降低。在厚度为370 nm时，薄膜具有良好的铁电性能和较低的漏电流，剩余极化P_r为12μC/cm²，漏电流密度为2.4×10^-6 A/cm²。     

（Pb0.3Sr0.7）1-xKxTiO3薄膜制备与介电调谐性能

采用溶胶-凝胶法在Pt/TiO2/SiO2/Si衬底上制备了多种不同组分的((Pb0.3Sr0.7)1-xKxTiO3)(x=0,1 mol%,2.5 mol%,5mol%多层均匀薄膜,井研究了它们的介电调谐性能.发现掺杂后薄膜的相结构没有发生变化,晶粒尺寸明显减小,介电常数降低及介电损耗减小.1MHz时,随K含量从0增加至5mool%,薄膜的介电常数从841降低至539,而介电损耗由0.134减小到0.0576,其微波介电综合性能改善.     

溶胶-凝胶法制备掺钙钛酸锶铋铁电薄膜

利用溶胶-凝胶法在Pt/Ti/SiO2/Si衬底上制备了CaxSr1-xBi4Ti4O15(CxS1-xBT,x=0～1)铁电薄膜.研究了不同Ca2取代量对薄膜的微观结构、取向生长、铁电性能以及介电性能的影响.结果表明:当Ca2 取代量为x=0.4时,C0.4S0.6BT铁电薄膜样品在一定程度上沿a轴择优取向;样品致密性较好,晶粒呈球型,且大小均匀,尺寸约为100nm.C0.4S0.6BT薄膜的剩余极化强度为8.37μC/cm2,矫顽场强为72kWcm;在1 Hz～1 MHz频率范围内,相对介电常数为234～219,介电损耗为0.009～0.073.     

溶胶-凝胶法制备Ba_(0.90)Sr_(0.10)Zr_xTi_(1-x)O_3成分梯度薄膜的介电性能

采用溶胶-凝胶法在Pt(111)/Ti/SiO2/Si衬底上制备Ba0.90Sr0.10ZrxTi1-xO3(BSZT)(x=0～0.40)组分及其成分梯度薄膜,研究各组分及梯度薄膜的相结构、显微结构及其介电性能。结果表明:随着Zr含量的增加,组分BSZT薄膜的相对介电常数(εr)和介电损耗(tanδ)降低,Curie温度向低温方向移动。与单相薄膜相比,成分梯度薄膜同时具有适中的相对介电常数(150εr300),低的介电损耗(tanδ0.014),高的材料优值(30)及良好的温度稳定性。     

SrBi_2Ta_2O_9薄膜的制备和铁电性能研究

用一种新的低温过程制备了SrBi2Ta2O9铁电薄膜。在Sol-Gel方法中用Pt/Ti/SiO2/Si作衬底,研究了薄膜的结构和电特性。SrBi2Ta2O9薄膜在淀积Pt上电极之前和之后都要退火,第一次退火在760乇氧压下600℃时退火30分钟,在第二次退火后薄膜结晶良好。     

(100)择优取向对0.935Bi_(1/2)Na_(1/2)TiO_3-0.065BaTiO_3-0.01Al_6Bi_2O_(12)无铅压电薄膜的结构和性能影响

通过激光脉冲沉积技术(PLD)在Pt(111)/Ti/SiO_2/Si(简称Pt)和具有LaNiO_3缓冲层的Pt(111)/Ti/SiO_2/Si(简称LNO/Pt)两种衬底上制备了0.935Bi_(1/2)Na_(1/2)TiO_3-0.065BaTiO_3-0.01Al_6Bi_2O_(12)(简称BNT-BT-AB)薄膜。利用X射线衍射仪、扫描电子显微镜、原子力显微镜和铁电分析仪等对薄膜的结构和性能进行了测试和表征。结果表明:Pt衬底上BNT-BT-AB薄膜为随机取向,晶粒形貌为立方块状,剩余极化强度2P_r=20.38μC/cm~2,介电可调为19%,局部有效压电系数d~*_(33)为130pm/V;LNO/Pt衬底上BNT-BT-AB薄膜呈现高度的(100)择优取向,薄膜表面平整,剩余极化强度2P_r=21.25μC/cm~2,介电常数(700)和介电可调性(23%)均大于随机取向薄膜,d~*_(33)提高到150pm/V。     

生长温度对单晶衬底上生长Ba(Zr_(0.2)Ti_(0.8))O_3薄膜微结构和介电性能的影响(英文)

采用脉冲激光沉积方法,在制备有LaNiO3(LNO)底电极的LaAlO3(LAO)衬底上,分别在500,600℃和700℃的沉积温度下制备了锆钛酸钡Ba(Zr0.2Ti0.8)O3(BZT)薄膜.通过X射线衍射表征薄膜的结构特性,原子力显微镜和扫描电子显微镜分别用来表征样品的表面和断面形貌.结果表明:BZT薄膜与LNO具有c轴取向,并以cube-on-cube方式排列生长.BZT薄膜表面致密无裂缝,具有柱状生长的晶粒.薄膜的介电性能测试显示:600℃下沉积的BZT薄膜具有较高的介电可调性(49.1%)和较低的介电损耗(2.5%).在600℃下沉积的BZT薄膜的优值因子(figure of merit,FOM)达到19.8.     

LSMCD法制备纳米(Pb,La)TiO3薄膜

研究了利用液态源雾化化学沉积(LSMCD)法制备纳米(Pb,La)TiO3薄膜的工艺. XRD和SEM分析表明:沉积4次,采用RCA热处理,在Pt/Ti/SiO2/Si基板上成功制备出具有钙钛矿结构的、晶粒粒径约60nm、厚度约180nm的纳米颗粒PLT薄膜.该方法既可以较精确的控制薄膜的化学计量比及掺杂浓度,又可采用控制超声雾化沉积的时间和次数来有效的控制膜厚及晶粒的大小.该工艺的沉积速率约为3nm/min.     

Effect of Orientation on the Ferroelectric Behavior of (Pb,Sr)TiO3 Thin Films

Pb_0.6Sr_0.4TiO₃ (PST) ferroelectric thin films were prepared on two different substrates by sol–gel methods. Films derived on the LaNiO(LNO)/Pt/Ti/SiO₂/Si substrates showed a strong (100) preferred orientation. The PST thin films grown on the LNO/Pt/Ti/SiO₂/Si(100) substrate showed a non-uniform rounded grain size distribution and have a larger polarization and lower coercive field E _c. The dependence of electrical properties derived on the Pt/Ti/SiO₂/Si and LNO/Pt/Ti/SiO₂/Si substrates has been studied, with a focus on the change of dielectric constant versus direct current (DC) bias field. The dielectric and ferroelectric properties of the Pb_0.6Sr_0.4TiO₃ thin films deposition on two kinds of substrates were investigated as a function of temperature, frequency and DC bias field.     

Dependence of the properties of compositionally graded Pb(Zr,Ti)O3 ferroelectric films of the bottom electrode

Compositionally graded Pb(Zr_,Ti)O₃ thin films were prepared on the Pt(1 1 1)/Ti/SiO₂/Si, LNO/Si(1 0 0) and LNO/Pt(1 1 1)/Ti/SiO₂/Si substrates by a modified sol–gel method and rapid heat-treatment. The composition depth profile of a typical up-graded film was determined using a combination of auger electron spectroscopy and Ar-ion etching. The crystallographic orientation and the microstructure of the resulting graded PZT thin films on the different substrates were characterized by XRD. The dielectric and ferroelectric properties of the graded PZT films were discussed. The graded PZT films on LNO/Pt/Ti/SiO₂/Si and LNO/Si(1 0 0) substrates have larger dielectric constant and remnant polarizations compared to that grown on Pt/Ti/SiO₂/Si substrates.     

Enhanced dielectric tunability properties of Ba(ZrxTi1−x)O3 thin films using seed layers on Pt/Ti/SiO2/Si substrates

The compositionally graded and homogeneous Ba(Zr_xTi_1−x)O₃ (BZT) thin films were fabricated on LaNiO₃ (LNO) buffered Pt/Ti/SiO₂/Si and Pt/Ti/SiO₂/Si substrates by a sol–gel deposition method, respectively. These films crystallized into a single perovskite phase. The BZT thin films deposited on LaNiO₃/Pt/Ti/SiO₂/Si substrates had a highly (1 0 0) preferred orientation and exhibited a preferred (1 1 0) orientation when the thin films were deposited on Pt/Ti/SiO₂/Si substrates. The LNO and Ba(Zr_0.30Ti_0.70) served as seed layer on Pt/Ti/SiO₂/Si substrates and analyze the relationship of seed layer, microstructure and dielectric behavior of the thin films. The compositionally graded thin films from BaTiO₃ to BaZr_0.35Ti_0.65O₃ were fabricated on LNO/Pt/Ti/SiO₂/Si substrates. The tunability behavior of compositionally graded films was analyzed in order to produce optimum effective dielectric properties. The dielectric constant of BaZr_xTi_1−xO₃ compositionally graded thin films showed weak temperature dependence. This kind of thin films has a potential in a fabrication of a temperature stable tunable device.     

Thickness Dependence of Dielectric,Leakage, and Ferroelectric Properties of Bi6Fe2Ti3O18 Thin Films Derived by Chemical Solution Deposition

We prepared Bi₆Fe₂Ti₃O₁₈ thin films on Pt/Ti/SiO₂/Si substrates with thickness ranging from ～300 to ～900 nm by using a chemical solution deposition route and investigated the thickness effects on the microstructure, dielectric, leakage, and ferroelectric properties of Bi₆Fe₂Ti₃O₁₈ thin films. Increasing thickness improves the surface morphology, dielectric, and leakage properties of Bi₆Fe₂Ti₃O₁₈ thin films and a well‐defined ferroelectric hysteresis loops can form for the thin films with the thickness above 400 nm. Moreover, the thickness dependence of saturation polarization is insignificant, whereas the remnant polarization decreases slightly with increasing thickness and it possesses a maximal value of ～20 μC/cm² for the 500 nm‐thick thin films. The mechanisms of the thickness dependence of microstructure, dielectric, and ferroelectric properties are discussed in detail. The results will provide a guidance to optimize the ferroelectric properties in Bi₆Fe₂Ti₃O₁₈ thin films by chemical solution deposition, which is important to further explore single‐phase multiferroics in the n = 5 Aurivillius thin films.     

静电雾化沉积制备PbTiO3薄膜的研究

采用静电雾化沉积技术制备了PbTiO3薄膜,探索了沉积温度和沉积时间对所制备薄膜的结构和形貌的影响.通过调节制备工艺,制备了多孔和致密的PbTiO3薄膜.测试了所制备钛酸铅薄膜的介电频率特性,在100kHz的介电常数和介电损耗分别为222和0.0247.     

TEM Characterization of Single- and Multilayer Triol-Based Sol–Gel PZT (53/47) Thin Films

Integrated lead zirconate titanate thin films deposited on Pt/Ti/SiO₂/Si substrates using a novel triol-based route were characterized using X-ray diffraction and transmission electron microscopy. Crack-free single-layer PZT films of up to 200 nm thick were prepared by triol-based sol–gel processing onto Pt/Ti/SiO₂/Si substrates. Films ∼75 nm thick exhibited a microstructure free of pores and second phase. As film thickness increased, film texture changed from {100} to {111} perovskite. Essentially, single-phase multilayer films could be prepared by the deposition and pyrolysis of several 75 nm layers, followed by a single crystallization step. The influence of heat-treatment schedule on the microstructure and orientation of the multilayer films is discussed. Comparison has been made between multilayer films prepared using the triol-based sol and an inverted mixing order/acetic acid-based sol.