热处理工艺对钙锶铋钛铁电薄膜性能的影响

用溶胶-凝胶法和快速退火技术在带白金电极和钛过渡层的硅片(Pt/Ti/SiO2/Si)上制备了钙锶铋钛(Ca0.4Sr0.6Bi4Ti4O15,CsBT-0.4)铁电薄膜.结果表明:退火温度及保温时间对CSBT-0.4铁电薄膜的微观结构、晶粒取向以及铁电性能的影响较大.x射线衍射谱表明:退火温度为750℃、保温时间为5min,得到的CsBT-0.4铁电薄膜样品的晶粒大小较均匀且致密性好,而且晶粒以a轴取向的球状晶粒为主,剩余极化强度(2Pr)和矫顽场(2Ec)分别为16.2 μC/cm2和130kV/cm.     

Pb用量对锆钛酸铅薄膜微观结构和铁电性能的影响

在Pt/Ti/SiO2/Si基片上,通过多次匀胶旋涂-预热处理工艺制备了PbTiO3(PT)无机薄层夹心的锆钛酸铅(lead zirconate titanate,PZT)薄膜,然后经650℃退火处理得到了所需的具有钙钛矿结构的PZT铁电薄膜.用X射线衍射、原子力显微镜表征了PZT铁电薄膜微观结构,并测试铁电性能.结果表明:制备PT层时的Pb用量对得到的PZT铁电薄膜的微观结构和铁电性能有重要影响.当Pb过量15%(摩尔分数)左右时,得到的PZT铁电薄膜不仅晶界清晰,晶粒尺寸分布均匀,具有纯钙钛矿结构,而且铁电性能优异,剩余极化强度Pr=21μC/cm2,矫顽场Ec=37kV/cm.     

溶胶-凝胶法制备SrBi2Ta2O9(SBT)铁电薄膜的研究

以乙醇钽、醋酸锶和硝酸氧铋为原材料,乙二醇单甲醚为溶剂,可以获得稳定的SBT溶胶和凝胶.采用Pt/Ti/SiO2/Si基片,通过溶胶-凝胶法在800℃经快速热处理制备出钙钛矿相SBT薄膜.XRD结果分析表明,薄膜的择优取向为(115)和(008),其饱和极化强度和剩余极化强度分别为Ps=8.8μC/cm2,Pr=5.2μC/cm2.     

化学溶液沉积法制备Bi4Ti3O12铁电薄膜及其性质的研究

报道了用化学溶液沉积法采用价格低廉的原料在电阻率为6～9Ω·cm的n型Si(100)衬底上生长Bi4Ti3O12铁电薄膜,并对薄膜的性质进行了研究。结果表明此制膜工艺简单,成本低,制备的Bi4Ti3O12铁电薄膜具有较低的结晶温度,且薄膜均匀,致密,无裂纹。在650℃下退火30min时得到的Bi4Ti3O12铁电薄膜具有良好的绝缘性和铁电性,薄膜的剩余极化Pr＝4.9μC/cm2,矫顽电场Ec＝87kV/cm。     

化学溶液沉积法制备Bi4Ti3O12铁电薄膜及其性质的研究

报道了用化学溶液沉积法采用价格低廉的原料在电阻率为 6～ 9Ω·cm的 n型 Si( 1 0 0 )衬底上生长 Bi4 Ti3 O12 铁电薄膜 ,并对薄膜的性质进行了研究。结果表明此制膜工艺简单 ,成本低 ,制备的 Bi4 Ti3 O12 铁电薄膜具有较低的结晶温度 ,且薄膜均匀 ,致密 ,无裂纹。在 650°C下退火 30 min时得到的 Bi4 Ti3 O12 铁电薄膜具有良好的绝缘性和铁电性 ,薄膜的剩余极化 Pr=4.9μC/cm2 ,矫顽电场 Ec=87k V/cm     

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.     

Bi5FeTi3O15薄膜室温多铁性及其磁性机理

用溶胶凝胶工艺在Pt/Ti/SiO2/Si基片上沉积了Bi5FeTi3O15(BFTO)薄膜,研究了前驱液浓度和退火升温速率对BFTO薄膜结晶的影响,前驱液浓度低于0.05mol/L时不利于4层层状钙钛矿结构的形成。沉积BFTO薄膜的最佳制备工艺为:前驱液浓度为0.05mol/L和氧气氛中退火速率为4℃/s。室温下,用最佳工艺制得的BFTO薄膜显示出良好的铁电性,在300 kV/cm的外加电场下,样品的剩余极化强度2Pr达到43.4μC/cm2;同时,BFTO薄膜也显示出弱铁磁性。为了研究其磁性来源,分别在氧气氛和氮气氛下对BFTO薄膜样品进行退火,分析其磁性的差异。认为BFTO薄膜室温下的弱铁磁性主要来源于F中心交换作用。     

PMnS-PZN-PZT压电纤维的制备与铁电性能

采用固相法制备了0.8Pb(Mn1/3Sb2/3)0.05(Zr1/2Ti1/2)0.95O3–0.2Pb(Zn1/3Nb2/3)0.28(Zr1/2Ti1/2)0.72O3(PMnS–PZN–PZT)粉末,然后用塑性聚合物方法制备了PMnS–PZN–PZT压电纤维。研究了纤维夹持状态对其铁电性能的影响。结果表明:塑性聚合物法制备的PMnS–PZN–PZT压电纤维具有良好的铁电性能,压电纤维处于自由状态时,剩余极化强度和矫顽场分别为85.4μC/cm2和8.5kV/cm,但电滞回线很难饱和。将纤维采用环氧树脂固化后,剩余极化强度变成39.2μC/cm2,电滞回线呈饱和状态,说明夹持状态对纤维的铁电性能产生很大的影响。高压下压电纤维浇铸前后的漏电流测试结果表明,压电纤维浇铸后剩余极化强度变小主要与漏电流有关。     

La/Nb掺杂对Bi_4Ti_3O_(12)薄膜铁电性能和疲劳特性的影响

采用溶胶–凝胶工艺(sol–gel)在Pt/Ti/SiO2/p-Si衬底上分别制备Bi4–xLaxTi3O12和Bi4Ti3–yNbyO12铁电薄膜,研究La/Nb掺杂对Bi4Ti3O12薄膜铁电性能和疲劳特性的影响。结果表明:La/Nb掺杂均能有效改善Bi4Ti3O12薄膜的铁电性能和疲劳特性。当La摩尔(下同)掺量在0.5～0.75时,La掺杂对Bi4Ti3O12薄膜的性能改善作用最好,而且在明显提高薄膜铁电性能的同时,对薄膜疲劳特性的改善更加显著,薄膜经1010极化反转后,其剩余极化强度(Pr)仅下降5.1%。Nb掺杂对提高薄膜铁电性能的作用更加明显,Nb掺量为0.06时,Bi4Ti3–yNbyO12薄膜的Pr高达18.7μC/cm2,但Nb掺量不宜过多,当Nb掺量超过0.06以后,薄膜的铁电性能和疲劳特性均反而有所下降。     

(1-x)Sr_2Bi_4Ti_5O_(18)-xBiFeO_3复合铁电薄膜的制备及性能研究

用溶胶-凝胶法结合层层退火工艺制备出(1-x)Sr_2Bi_4Ti_5O_(18)-xBiFeO_3(SBFTi-x,x=0.1-0.4)系列薄膜,对样品进行分析研究,发现随着BFO取代量x的增加,SBFTi-x复合薄膜的铁电性能逐渐提高。当BiFO_3(BFO)的取代量为0.3,测试电场为931 KV/cm时,剩余极化强度2Pr=23.4μC/cm~2,矫顽场2Ec=28.0 KV/cm,漏电流密度较小。对薄膜样品的漏电流曲线进行线性拟合,发现当测试电场强度低于230KV/cm时,曲线的拟合斜率ɑ都接近于1,说明薄膜内部的漏电流导电机制是以欧姆传导(ɑ≈1)为主,而测试场强高于230 KV/cm时,其导电机制为FN隧道效应。     

Antiferroelectric titanium-doped zirconia thin films deposited via HiPIMS for highly efficient electrocaloric applications

In this study, the antiferroelectric (AFE) and electrocaloric (EC) characteristics of lead-free titanium (Ti)-doped zirconia (ZrO₂) thin films deposited via high-power impulse magnetron sputtering (HiPIMS) were investigated. The argon-to-oxygen ratio was initially optimized during deposition to obtain a more stoichiometric ZrO₂ film for enhanced antiferroelectricity. Furthermore, enhanced crystallinity was achieved through the incorporation of Ti atoms into ZrO₂ thin films as confirmed via grazing incidence X-ray diffraction and high-resolution transmission electron microscopy. For metal-insulator-metal capacitors with Ti-doped ZrO₂ thin films, the AFE behaviors were significantly improved because of the excellent crystallinity of the tetragonal phase. Based on a fast polarization response and robust fatigue resistance under a 10⁶-cycle endurance test, the EC effect was successfully explored, and an adiabatic temperature change (ΔT) of ?14.8 K was realized. With competitive EC properties, Ti-doped ZrO₂ thin films deposited via HiPIMS are proposed as promising candidates for use in future cooling systems.     

SmCo/Cr磁性薄膜的工艺与性能

通过对磁控溅射条件的优化,制备出了较理想的 SmCo(Al,Si)/Cr硬盘磁记录介质。退火处理后又得到较好的硬磁薄膜。结果表明, Sm含量在 31.6％ atm,Cr缓冲层为 66 nm, Sm(CoAlSi)5磁性层为 30 nm等条件下,制得的 Sm(CoAlSi)5/Cr薄膜的矫顽力 (Hc)为 187.8 kA/m(2.36 kOe),矩形比 (S=Mr/Ms)≈ 0.94;在 500℃保温 25 min退火后,矫顽力 (Hc)达 1042.5 kA/m(13.1 kOe),矩形比 (S)≈ 0.92。     

Enhancement of the piezoelectric property in PMN-PZT/PZT thin films

0.3Pb(Mg_1/3Nb_2/3)O₃-0.7Pb(Zr_0.52Ti_0.48)O₃/Pb(Zr_0.52Ti_0.48)O₃ (PMN-PZT/PZT) piezoelectric films have been deposited on Pt/Ti/SiO₂/Si substrates via in-situ magnetron sputtering process. The purpose of this work was to investigate heterogeneous interfaces-dependent preferential orientation, micro-morphology, and piezoelectric behaviors of the PMN-PZT/PZT films. Uniform and dense columnar grains are observed by Scanning electron microscope (SEM) analysis as increasing the number of hetero-interfaces. For the film with five heterogeneous interfaces (H5), the superior ferroelectricity (2P_r = 21.6 μC/cm², 2E_c = 60 kV/cm) and dielectricity (ε_r = 1012.1, tanδ = 0.022 at 1 kHz) are obtained, which arises from highly dense columnar grain and the influence of heterogeneous interface strain. Moreover, an excellent piezoelectric constant e₃₁ of 8.2C/m² is achieved in H5 film, which is 3.5 times larger than that of PZT film. It is expected that this study will simulates the design and synthesis of new functional materials, and provides a guidance for actuators device fabrication and applications.     

ITO薄膜的制备工艺及进展

对玻璃表面ITO膜的组成、导电机制、性质和制备工艺进行描述.介绍各种制备工艺的优点及在今后的研究中要解决的问题.     

Bipolar high-power impulse magnetron sputtering synthesis of high-entropy carbides

In this study, we report high-entropy carbides synthesis with reactive bipolar high-power impulse magnetron sputtering (HiPIMS). Uncontrolled microstructure and stoichiometry development with reactive gas flow rate are major limitations of conventional direct current (DC) and radio frequency (RF) magnetron sputtering of multicomponent carbides. With HiPIMS these chemically disordered crystals structurally and compositionally transform from a carbon-deficient metallic (C/M < 1), to a stoichiometric ceramic zone (C/M ∼ 1), and to a nanocomposite embodiment (C/M > 1), as a function of the carbon content during HiPIMS deposition. X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and nanoindentation hardness measurements are combined to demonstrate the three regions of synthesis domain. HiPIMS provides access to metallic, ceramic, and composite carbides with great control over the microstructure and stoichiometry, which is elusive in case of conventional DC and RF magnetron sputtering. Notably, the stoichiometric ceramic zone maintains a constant carbon to metal ratio (C/M ∼ 1) over an extended amount of methane flow before transitioning to a nanocomposite microstructure (C/M > 1). The transition zone breadth depends on materials affinity for carbon that correlates with valence electron concentration (VEC). As such, synthesis conditions for new high-entropy carbides can be understood and predicted based on VEC.     

Poly(methyl methacrylate) as masking material for microelectromechanical system (MEMS) fabrication

In the present study direct current (dc) sputtered poly(methyl methacrylate) (PMMA) films deposited on silicon substrates were evaluated as masking materials for anisotropic etching of silicon in aqueous potassium hydroxide (KOH) and tetramethyl ammonium hydroxide (TMAH) solutions. Sputtered PMMA films were characterized by FTIR to ascertain the bonding, by X‐ray photoelectron spectroscopy (XPS) for the elemental composition, and by the contact angle for measuring the adhesion of the film with the substrate. FTIR and XPS data showed the presence of a poly(tetrafluoroethylene)‐like film on the silicon substrate. The interfacial tension was calculated from the contact angle value, which was 0.82 dyne/cm, confirming good adhesion of the film and the substrate. A pattern was lithographically transferred through the masking material on the silicon substrate, and the etch rate of the masking layer was calculated from the masking time data of the films. The etch rate value of 4 Å/min obtained for the masking material is low compared to the etch rate of the conventional masking materials (60 Å/min for SiO₂ and 8 Å/min for Si₃N₄). © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2094–2098, 2006     

Effect of the thicknesses of the Al2SiO5 ion conductor on the opto-electrical properties for all-solid electrochromic devices

In this study, an all-solid-state electrochromic device (ECD) with the structure of ITO/WO₃/Al₂SiO₅/NiO_x/ITO was prepared, and the effect of the Al₂SiO₅ solid electrolyte thicknesses on the opto-electrical performance was investigated. The microstructure and surface morphology were characterized using XRD, SEM and AFM, and the surface morphology and degree of surface looseness demonstrate a significant influence on the opto-electrical properties of ECDs. The charge transfer dynamics at the solid-solid interface were characterized using EIS to obtain an ionic conductivity of 4.637 × 10^-8 S/cm. CV, CA and UV–Visible spectra were employed to record the in situ electrochemical and optical properties. The results revealed that the highest optical modulation was 44.58%, the coloring and bleaching times were 14.8 s and 3.7 s, and the highest coloring efficiency was 98.17 cm²/C, which indicates that excellent opto-electrical properties were obtained. When the thickness increases, the degree of surface dense morphology transforms, and the loose morphology is more favorable for ion conductivity, which improves the opto-electrical properties. The results in this study provide insights into the understanding of Al³⁺-based all-solid-state ECDs, which promote the exploration of new types of Al³⁺ ionic conductors for all-solid-state ECDs.     

纳米Fe微粒的溅射制备及粒度计算

运用溅射方法,通过控制溅射时间、氢气压强和Al2O3与Fe的比例,制备了粒子直径35A～90A的纳米铁微粒薄膜。并对纳米微粒进行了计算和电镜观察。     

Heteroepitaxial growth of TiN film on MgO (100) by reactive magnetron sputtering

TiN thin films were deposited on MgO (100) substrates at different substrate temperatures using rf sputtering with Ar/N₂ ratio of about 10. At 700°C, the growth rate of TiN was approximately 0.05 μm/h. The structural and electrical properties of TiN thin films were characterized with x-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Hall measurements. For all deposition conditions, XRD results show that the TiN films can be in an epitaxy with MgO with cube-on-cube orientation relationship of (001)_TiN // (001)_MgO and [100]_TiN // [100]_MgO. TEM with selected-area electron diffraction pattern verifies the epitaxial growth of the TiN films on MgO. SEM and AFM show that the surface of the TiN film is very smooth with roughness approximately 0.26 nm. The minimum resistivity of the films can be as low as 45 μΩ cm.     

Effects of calcination condition on expansion property of MgO-type expansive agent used in cement-based materials

Previous research indicated that the expansion property of MgO-type expansive agent (MEA) depended strongly on the calcining conditions, i.e. kiln temperature and residence time. However, the intrinsic effect of calcination condition on the expansion property of MEA has not been clearly demonstrated. In the present work, the effects of calcination condition on the microstructure, hydration activity, and expansion property of MEA have been investigated, and their correlations are also studied. Results indicate that the microstructure of MEA is the intrinsic factor that controlling its expansion property, which is influenced by the calcination condition. MEA produced under higher temperature and longer residence time has less interior pores, larger crystal size of MgO, and smaller specific surface area, thus resulting in lower hydration activity and slower expansion at early age, but larger “ultimate” expansion at late age. While, a new expansion model of MEA is proposed to explain these results.