用辉光放电等离子体制备湿敏膜的研究

本文应用射频辉光放电等离子体技术在电容式耦合反应室内制备等离子体聚苯乙烯（ＰＰＳ）膜，采用铝膜－聚合膜－金膜的平板电容器结构研究了聚合膜电容器的电容量随湿度变化的特性。结果表明，等离子体聚合膜电容器对湿度变化的响应时间在１．５ｍｉｎ之内，湿滞和温度系数小。此外，还分析了聚合膜的结构并讨论膜结构与湿敏性能的关系。     

溶胶-凝胶法制备Ni_(0.4)Cu_(0.2)Zn_(0.4)Fe_xO_4薄膜研究

利用溶胶-凝胶方法在硅基片上制备了NiZnCu系列铁氧体薄膜,研究了溶胶pH值、溶胶陈化条件、原料配比、热处理工艺对样品磁性能的影响。发现溶胶的pH值为3.2时得到的样品矫顽力较小。将溶胶在不同温度下陈化,制得样品的矫顽力Hc随溶胶陈化放置时间逐渐减小然后趋于稳定,其中由常温下放置的溶胶制得样品的矫顽力较小且最先稳定。将Ni0.4Cu0.2Zn0.4FexO4(x=1.9,2.0,2.1)配方的薄膜在不同温度条件下热处理,发现x=2.0的样品性能较好。在600℃附近热处理6min,可以得到矫顽力Hc较低而饱和磁化强度Ms较高的样品:矫顽力最低可达1329 A/m,饱和磁化强度约为290kA/m。     

Characterization of Ni/Ce Co-Doped BST Thin Film Grown on LSCO/Pt Electrodes Prepared by Pulsed Laser Deposition

Perovskite (Ba_0.6Sr_0.4)TiO₃ (BST) thin films doped with Ni, Ce and Ni/Ce codopants were prepared on LSCO/Pt/SiO₂/Si substrates by pulsed laser deposition method. In this study, La_0.5Sr_0.5CoO₃ (LSCO) bottom electrodes were used to improve the crystallinity and dielectric properties of BST films. Single ion doped(1 mol%Ni doped,1 mol%Ce doped) BST films showed more improved crystallinity, smoother surface, and smaller grain size than that with 1 mol%Ni/1 mol%Ce. The dielectric constant and loss of Ni/Ce co-doped BST films were about 298 and 1.8%, respectively. In addition, tunability and figure of merit of co-doped BST films showed minimum values of approximately 9.3% and 5, respectively. With 1% Ni-doped BST thin films, results gave a tunability of 54.2% and a loss tangent of 1.8% while a figure of merit was 30. Correlation of the material properties with dielectric and tunable properties suggests the 1 mol%Ni-doped BST films are effective potential candidate for tunable device applications.     

锂掺杂p型氧化锌薄膜的制备

通过将含有原子百分含量为2%锂(2at%)的锌锂(Zn-Li)合金薄膜在500℃氮气氛中退火2 h,然后在700℃氧气氛下退火1 h的方法分别制备出p型锂掺杂的氧化锌(ZnO:Li)薄膜。通过He-Cd激光器的325 nm线激发,测量了样品低温(12 K)发光光谱,并根据Zn-Li合金薄膜的低温发光光谱特征,计算出(LiZn-N)复合受主能级的位置位于价带顶137 meV处。     

磁控溅射对薄膜附着力的影响

磁控溅射技术因具有溅射速率高、无污染、可制备各种不同功能的薄膜等优点而得到广泛地应用。综述了薄膜附着力机理,分析了影响薄膜性能的因素,结果表明,薄膜的附着力是影响薄膜性能的主要因素。影响薄膜附着力的因素有:基材的表面清洁度、制备薄膜的各种工艺参数、热处理、原料的纯度等。     

Preparation of Barium Strontium Titanate Thin Film by Spray Deposition

Barium strontium titanate ((Ba,Sr)TiO 3 ; BST) thin films were prepared on platinum-coated silicon substrates using spray deposition. The spray condition (substrate temperature and chamber pressure) dependence on surface roughness for the fired BST thin films was investigated. We obtained BST films thinner than 100 nm on the following properties. Average roughness (Ra) and peak-to-valley value (Rmax) were 3.9 and 130 nm. Dielectric constant and dissipation factor at 1 kHz were 250 and 1.6%. These excellent properties were obtained with even thickness. This method is considered to be advantageous for use with electronic devices that have thin dielectric layers, which make for thin films.     

Orientation Control of (Bi,La) 4 Ti 3 O 12 Thin Films by Addition of Silicates and Germanates

Orientation of crystallites in (Bi,La) 4 Ti 3 O 12 (BLT) thin films were successfully controlled by adding such silicates and germanates as Bi 2 SiO 5 , ZrSiO 4 and La 2 GeO 5 . The ferroelectric films were formed by spin-coating mixed sol-gel solutions of BLT and silicate or germanate on a Pt/Ti/SiO 2 /Si structure. It was found from XRD analysis that the preferred orientation of crystallites in the BLT films was changed by the additives. That is, the orientation of crystallites in a Bi 2 SiO 5 -added BLT film was random, while it was almost perfectly c-axis-oriented in La 2 GeO 5 -added BLT and it was strongly (117)-oriented when ZrSiO 4 was added to BLT. It was also found that the remnant polarization and coercive field changed reflecting these different orientations.     

Photoluminescence of ZnO:Ga Thin Films Fabricated by Pulsed Laser Deposition Technique

Highly c-axis oriented Ga-doped ZnO films (GZO) have been grown on sapphire (0001) substrates by pulsed laser deposition (PLD) method. Photoluminescence (PL) spectra indicate that Ga atoms have a large effect on the luminescent properties of ZnO films. PL spectra of GZO films show near band edge (NBE) emissions and broad orange deep-level emissions. The NBE emission shifts to higher energy region and the intensity decreases with the increase of Ga concentration. The blue shift of NBE emission results from Burstein-Moss effect. The quenching of NBE emission is ascribed to the noradiative recombination. The orange emission is related to the oxygen vacancies.     

CVD法制备的碳包覆(Fe,Co)纳米粒子的结构及电磁特性

以溶胶—凝胶超临界干燥技术合成的含Fe、Co双金属的SiO2纳米气凝胶为催化剂，采用CVD法高温气相催化裂解甲烷的方法合成了碳包覆铁钴的C—(Fe，Co)／SiO2纳米复合材料。用透射电子显微镜(TEM)，X射线衍射仪(XRD)等对材料的形貌、相结构进行了检测，并采用微波矢量网络分析仪测量了微波频率下材料的复介电常数～↑ε和复磁导率～↑μ。实验表明，C-(Fe，Co)/SiO2纳米复合材料中含有大量碳包覆(Fe，Co)粒子及少量纳米碳管，其中碳包覆（Fe,Co)纳米粒子主要呈球形和椭球形，包覆层为约20层的石墨层；另还有少量的纳米碳管，其端部包覆有不同粒径酌纳米粒子，所制备的复合材料中铁和钴的比例对材料的电磁参数影响较大。     

The Study of Ferroelectric La-Doped PbTiO3 Thin Films Prepared by RF Magnetron Sputtering

Ferroelectric La-modified lead titanate (PLT) thin film were grown on Pt/Ti/SiO2/Si by sputtering the Pb_0.93La_0.07TiO₃ targets containing an amounts of excess 8% PbO. The effects of sputtering and annealing conditions on the crystalline structures and the surface morphologies of the PLT thin films have been investigated. The remanent polarization (Pr) and the coercive field of the PLT film through rapid thermal annealing (RTA) was 10.2 μC/cm² and 45 kV/cm respectively. The maximum pyroelectric coefficient reached 19 nC/cm².K at 20°C.     

圆环薄膜型介电弹性体换能器发电量影响因素研究

介电弹性体是一种新型的柔性智能材料,与风能、水能、潮汐能相结合,可以用来收集电能量。为了研究影响圆环薄膜型介电弹性体换能器发电量的因素,首先在恒电荷工作方式下,通过对圆环薄膜型介电弹性体换能器的数学模型进行分析,在不考虑内部损耗的情况下,确定了介电弹性体换能器发电量影响因素,然后做初步试验确定各因素对发电量影响的规律。最后通过IBM SPSS Statistics 25软件设计正交试验来确定介电弹性体换能器发电量影响因素的主次顺序。研究结果表明：介电弹性体换能器发电量影响因素的主次顺序分别为固定介电弹性体薄膜的内框半径和外框内半径长度的比例、偏置电压、柔性电极材料、拉伸位移。     

电化学浸渍镍电极结构的研究

采用镍电极电化学浸渍工艺,取代目前一直使用的真空化学浸渍工艺,用于氢镍电池、镉镍电池和锌镍电池的制造,可提高电池的工作性能和寿命.介绍了用现代物理测试手段对电化学浸渍镍电极结构的研究,探讨了其性能优越的原因.     

The Characteristics of Magnesium Titanate Thin Film as Buffer Layer by Electron Beam Evaporation

We have studied the application of magnesium titanate thin films as buffer layer for the improvement of adhesion of Pt films to Si substrate. Magnesium titanate films were successfully prepared on Si(100) substrate by electron beam evaporation. The crystal phase of MgTi₂O₅ and MgTiO₃ films on Si substrate were observed. These films had a very smooth and densely packed surface morphology and showed a good characteristic as the adhesion layer for Pt. Also, AES analysis showed the excellent properties as the reaction barrier layer between Pt and Si.     

Effect of Solution Processing on PZT Thin Films Prepared by a Hybrid MOD Solution Deposition Route

Lead zirconate titanate, Pb(Zr_0.53Ti_0.47)O₃ (PZT), thin films were prepared by a hybrid metalorganic decomposition (MOD) solution deposition route; the effects of processing conditions on the film structure and properties were investigated. Solutions were synthesized by mixing and reacting Zr acetylacetonate and Pb acetate trihydrate with a solution prepared from Ti isopropoxide, acetic acid and water. Chemical changes in the solution during preparation and solution storage (i.e., aging) were investigated by visual observation and FTIR, and were evidenced by changes in phase content and properties of the final PZT films. Results suggest that Zr acetylacetonate and Pb acetate trihydrate react with a Ti oxoacetate-based precursor, and that this reaction continues during aging at room temperature. The PZT film quality and properties improved with aging time of the solution before deposition. To achieve good properties and design a convenient processing route, an accelerated aging scheme, including a brief aging at 60°C and freezing to prevent further reaction, was developed. PZT films prepared from these solutions had average dielectric constants of 1040, loss tangents of 0.05, remnant polarizations of 26 C/cm², and coercive fields of 39 kV/cm.     

Control of Crystallographic Structure of Aluminum Nitride Films Prepared by Magnetron Sputtering

Aluminum nitride (AlN) films were prepared by using reactive magnetron (RMS). The substrate temperature (T_s) was varied from room temperature to 700°C, and RF power (P _w) from 100 to 250 W, and three different substrate materials (e.g. Si(100), Pt(111)/Si(100) and Al₂O₃(00·1)) were used. The mean free path of the species in the vacuum was controlled to be much shorter than the target-to-substrate distance, so that T_s and P _w have the equivalent effect in affecting the effective thermal energy of the species after landing on the substrate. With these conditions, the film structure was found to cover a broad range, varying from nearly amorphous (na-), polycrystalline (p-), (00·1) texture (t-) and epitaxial (e-) structure. The structural change is supposed to be governed the successive increase in the thermal energy of the species on the substrate. The use of substrate material having lattice matching with the AlN structure further assists the (00·1) preferential growth when the species are mobile enough at the settings of high T_s and P _w.     

Studies of ZnO Thin Films On Sapphire (0001) Substrates Deposited by Pulsed Laser Deposition

ZnO thin films are deposited on sapphire (0001) substrates at different temperatures in the pulsed laser deposition (PLD) system. By measurements of X-ray diffraction (XRD), atomic force microscopy (AFM), and Photoluminescence (PL) at room temperature, fabrication temperatures higher than 400C is found to be the optimum condition for the structural and optical properties of ZnO thin films. With the increase of the fabrication temperature, the grain size becomes bigger and the thin film becomes more homogeneous. In order to get the high-quality ZnO thin film at low temperature, ZnO thin films are deposited at room temperature and annealed in a rapid thermal annealing (RTA) system. It is found that the optical property of the thin film can be greatly improved by annealing in RTA system.     

基于DSP的电影洗印自动控制系统

根据国内电影洗印工艺及自动化现状,提出了基于DSP的电影洗印工艺自动化控制系统的设计方案.采用32位DSP芯片TMS320F2812和图形化设计软件LabVIEW实现了数据的实时采集和洗片过程的实时监控,并可以对洗片温度,pH值,电动调节阀开度,片种,流量这几项关键参数进行实时记录和网络传输.现场运行结果表明,系统稳定、可靠、操作方便,大大提高了工作效率.     

Structure and Properties of Preferential (110) Orientation BiFeO3 Thin Films by Sol-Gel Method

Abstract

Multiferroic materials, coexisting of ferroelectric, ferromagnetic and ferroelastic properties, possess potential applications in functional devices. BiFeO₃ (BFO) is a unique room temperature multiferroic material with high ferroelectric Curie temperature and Neel temperature. The BFO thin films were prepared on Si (111) substrate by sol-gel method in this paper. XRD analyses show that the thin films exhibit pure phase and preferred (100) orientation when annealing temperature is 500?°C. Field emission scanning electron microscopy shows that the crystallization degree of the films is getting better with the increase of annealing temperature. The thickness of the sample is about 400?nm. The hysteresis loop of BFO films annealing at 500?°C show 1.93?µC/cm² remnant polarizations. However, the hysteresis loop is not perfect, which may be caused by a large leakage current. The magnetic hysteresis loop of BFO films is tested as well, indicating that the BFO film is antiferromagnetic and the residual magnetization (Mr) and coercive field (Hc) of the BFO films were 0.054?emu/g and 1026.4?Oe, respectively.     

Aging and Annealing Effects of ZnO Thin Films on GaAs Substrates Deposited by Pulsed Laser Deposition

Zinc oxide (ZnO) thin films were deposited on GaAs (100) substrates at different temperatures in the pulsed laser deposition (PLD) system. From the measurements of X-ray diffraction (XRD) at room temperature, 300–500°C were found to be good condition for the crystallization of the thin films. From the photoluminescence (PL) measurements, 500°C was found to be the optimized temperature for its optical property. Samples grown at 100, 200, 300, and 400°C showed near band-edge (NBE) emissions and deep-level emissions. The intensity of deep-level emissions decreased as time goes on, which is believed to originate from oxygen vacancies or zinc interstitials in thin films. While for the sample grown at 500°C, bright NBE emissions were observed at room temperature, and no deep-level emissions observed. This means that the high-optical-quality thin film was grown at 500°C. At the same time, annealing process of ZnO thin films grown at room temperature was carried out in PLD chamber. It was found that the annealing temperature of 600°C has strong effects on its PL. Aging and annealing effects in ZnO thin films grown on GaAs substrates by PLD were observed for the first time.     

Ferroelectric Properties of Bi3.25Nd0.75Ti3O12 Thin Films Prepared by MOD Process

Ferroelectric Bi_{4 – x}Nd_xTi₃O₁₂(BNdT) thin films with the composition (x = 0.75) were prepared on Pt/Ti/SiO₂/Si(100) substrate by metal-organic deposition. The films were annealed by various temperatures from 550 to 650C and then the electrical and structural characteristics were investigated for the application of FRAM. Electrical properties such as dielectric constant, 2Pr and capacitance were quite dependent on the thermal heat treatment. The measured 2Pr value on the BNdT capacitor annealed at 650C was 56 C/cm² at an applied voltage of 5 V. No fatigue was observed up to 8 × 10¹⁰ read/write switching cycles at a frequency of 1 MHz regardless of annealing temperatures.