二氧化硅/ 聚酰亚胺纳米杂化薄膜室温及低温力学性能

利用溶胶-凝胶技术制备了不同SiO₂ 含量的二氧化硅/ 聚酰亚胺(SiO₂ / PI) 纳米杂化薄膜。采用红外光谱( IR) 和扫描电镜(SEM) 手段对该体系的分子结构和断裂形貌进行了表征, 研究了聚酰亚胺薄膜室温和低温(77K) 力学性能。结果表明: 室温和低温(77 K) 下, SiO₂ / PI 杂化薄膜的拉伸强度开始时均随SiO₂ 含量的增加而增加, 在含量为3 %时达到最大值, 低温下杂化薄膜的拉伸强度明显高于室温。室温下, 杂化薄膜的断裂伸长率在含量为3 %时达到最大值, 而低温(77 K) 下, 薄膜的断裂伸长率的变化没有呈现明显的规律性。      

基于MoS2/SiO2范德华异质结的VO2薄膜转移打印研究

近年来, 柔性电子器件由于在物联网、生物电子等领域的潜在应用引起了研究者的广泛关注。功能氧化物材料在柔性聚合物中的集成已被证明是实现高性能柔性电子器件的有效方式。由于功能氧化物薄膜通常需要高温制备, 直接在柔性聚合物基底上合成高质量的氧化物薄膜仍然是一个巨大的挑战。本研究提出了一种基于MoS₂/SiO₂范德华异质结转移打印大面积VO₂薄膜的方法, 即利用MoS₂和SiO₂薄膜亲疏水性能的不同, 可以仅使用去离子水解离MoS₂/SiO₂范德华异质结界面, 成功将Si/SiO₂/MoS₂/SiO₂/VO₂ 多层膜结构上的VO₂薄膜转印到Si、SiO₂/Si以及柔性基底上。X射线衍射(XRD)结果显示, 转印前后VO₂薄膜的晶体结构没有差异, 变温Raman光谱和变温红外反射光谱证明了转印前后VO₂薄膜良好的金属-绝缘体转变性能。本研究提供了一种有效的功能氧化物薄膜转印方法, 在不引入牺牲层和腐蚀性溶剂的条件下, 实现了VO₂薄膜在任意基底上的低温集成, 为柔性可穿戴电子器件的研制提供了一种新思路。     

基于干共混法控制柔性模板上金属薄膜微裂纹形貌

以500 nm的SiO₂纳米粒子为填料,聚二甲基硅氧烷(PDMS)为包覆纳米粒子的聚合物,通过一种新颖的干共混法制备了SiO₂纳米粒子含量高达83.8wt%的SiO₂/PDMS柔性模板。所制备柔性模板的弹性模量为16.58 MPa,热膨胀系数为96×10?6/℃,较SiO₂直接掺入PDMS中湿共混制备的纯PDMS柔性模板,弹性模量提高了91.56%,热膨胀系数降低了69.23%,且该柔性模板具有良好的透明度。最后,在柔性模板表面采用磁控溅射法沉积银薄膜,利用SEM和AFM对银薄膜表面形貌进行表征。结果显示,银薄膜表面光滑,粗糙度很小,且具有良好稳定性。干共混法制备的柔性模板有效抑制了金属薄膜微裂纹的产生,为制造导电性良好的电极及大面积的金属薄膜提供了新方案。      

阴极直接制备铜氧化物-SiO2复合薄膜及其电化学形成机理

以室温下制备出的n₍Cu²⁺)∶n₍Cit^3-)=2∶1的透明稳定的Cu(Ⅱ)-Cit^3--SiO₂复合溶胶为电解液，直接在氧化铟锡导电玻璃(ITO)阴极上电沉积得到铜氧化物-SiO₂复合薄膜。循环伏安(CV)和X射线衍射(XRD)结果表明，溶胶中Cu²⁺与吸附在电极上的SiO2溶胶共电沉积形成Cu₂O-SiO₂凝胶薄膜，XRD和计时安培(CA)结果表明，薄膜中的SiO₂量随过电位升高而减少。X射线光电子能谱(XPS)、XRD和能量色散X射线(EDX)结果表明，高过电位下，SiO₂和Cu(Ⅱ)借助析氢生成的OH^-共沉积，得到CuO/Cu₂O-SiO₂薄膜，这与扫描电子显微镜(SEM)图片显示的所得薄膜具有两种不同形貌的颗粒的结果一致。     

磷酸处理对多孔SiO2薄膜质子导电特性和双电层薄膜晶体管性能的影响

采用等离子体增强化学气相沉积法(PECVD)制备了多孔SiO₂薄膜, 系统地研究了不同浓度磷酸处理对多孔SiO₂薄膜的质子导电特性、双电层电容和以此多孔SiO₂薄膜为栅介质的铟锌氧(IZO)双电层薄膜晶体管性能的影响。结果表明: 多孔SiO₂薄膜的质子电导率和双电层电容随磷酸浓度升高而增大, 60%浓度磷酸处理后多孔SiO₂薄膜质子电导率和双电层电容分别达到1.51×10^-4 S/cm和6.33 μF/cm²。随磷酸浓度升高, 双电层薄膜晶体管的工作电压降低, 并且, 电流开关比也变大。其中60%浓度磷酸处理后器件工作电压为1.2 V, 迁移率为20 cm²/(V·s), 电流开关比为4×10⁶。这种双电层薄膜晶体管有望应用在化学和生物传感等领域。     

SiO2表面改性对高填充SiO2/聚四氟乙烯复合薄膜性能的影响

选用三种具有不同疏水官能团的硅烷偶联剂,即含苯基的偶联剂1(Ph-1)、含氟基的偶联剂2(F-2)和含环氧丙氧基的偶联剂3(GP-3)对SiO₂进行表面改性,并采用空气辅助干法共混、冷压烧结并车削成膜的方法制备了SiO₂填充量为35wt%、厚度为50 μm的SiO₂/聚四氟乙烯(PTFE)复合薄膜。改性后SiO₂在PTFE中分散均匀。研究了不同含量F-2对SiO₂/PTFE复合薄膜性能的影响,发现当含氟基的硅烷偶联剂F-2用量(与SiO₂质量比)为0.3%时,SiO₂/PTFE复合薄膜的针孔缺陷最少,拉伸强度由9.2 MPa提高至16.2 MPa;在10 GHz下,SiO₂/PTFE复合薄膜的介电常数由2.475降低至2.416,介电损耗由2.66×10?3降低至2.01×10?3,SiO₂/PTFE复合薄膜显示出优异的综合性能。      

基底偏压对Zr-B-O-N薄膜结构及性能的影响

二硼化锆(ZrB₂)薄膜因具有高熔点、低电阻率等特点,在硅基器件Cu互连工艺中具有广阔的应用前景。然而,沉积态ZrB₂薄膜多呈现结晶态,其晶界会为Cu原子提供快速扩散通道,通过非金属元素(N或O)掺杂可以得到非晶结构的ZrB₂薄膜,以提高其扩散阻挡性能。采用反应磁控溅射技术,在不同基底偏压下在单晶Si(100)基底上沉积了Zr-B-O-N薄膜和Cu/Zr-B-O-N双层膜,分别利用原子力显微镜、X射线衍射仪、透射电子显微镜、扫描电子显微镜和四点探针仪等检测方法对薄膜的微观组织结构、电学和扩散阻挡性能进行表征分析。研究结果表明：沉积态Zr-B-O-N薄膜表面平整,粗糙度随基底偏压增加而增加,且薄膜均呈现非晶结构;当基底偏压为150 V时,10 nm厚的非晶Zr-B-O-N薄膜可以在700℃有效阻挡Cu原子扩散。因此,Zr-B-O-N薄膜是一种具有应用潜力的扩散阻挡层材料。     

140℃高温下SiO2晶态对硅酸三钙水化产物的影响

目前，在G级油井水泥中加入SiO₂是降低其水化产物在温度高于110℃下力学性能衰退的主要手段。然而，SiO₂晶体形态不同，导致水泥水化产物不同，耐高温性能也不同。为了探究SiO₂晶体形态对水泥水化产物的影响，笔者以油井水泥的主要成分硅酸三钙(C₃S)为研究对象，采用核磁共振、X射线衍射、热重分析和扫描电镜以及能谱等手段分析了晶体SiO₂(石英砂)和非晶体SiO₂(微硅)对C₃S水化产物的影响。结果表明：SiO₂通过填充孔隙以及转化水化产物，能有效防止C₃S水化产物在高温下强度衰退，以及孔隙度和渗透率的增加。微硅比石英砂更活跃，能迅速与Ca(OH)₂发生火山灰反应生成次生水化硅酸钙。此外，SiO₂还能将高钙硅比的水化硅酸钙(针硅钙石(Ca₂SiO₃(OH)₂)、羟硅钙石(Ca_...     

微型超级电容器PPy/GO-RuO2复合膜电极的制备与电化学性能

为了解决氧化钌(RuO₂)沉积电位过高, 难以在三维微结构金属集流体上直接沉积的问题, 提出采用分步电沉积方法在微三维结构镍(Ni)集流体上制备RuO₂复合膜电极, 即先在三维微结构Ni集流体上沉积聚吡咯/氧化石墨烯(PPy/GO)薄膜作为基底, 经热处理后, 在基底上二次沉积出RuO₂颗粒, 最后再对RuO₂复合薄膜进行二次热处理。扫描电子显微镜(SEM)观察显示, 随着热处理温度的升高, 薄膜表面多孔结构增多, 达到了提高膜电极结构孔隙分布的目的。能量分散谱(EDS)和X射线光电子能谱分析(XPS)表明, 薄膜中无定形RuO₂·xH₂O的存在保证了膜电极的大比容量。电化学性能测试结果表明, 经105℃处理后的膜电极电化学性能最佳, 比电容为28.5 mF/cm², 能量密度为0.04 Wh/m², 功率密度为14.25 W/m²。采用分步电沉积方法制备出的RuO₂复合薄膜是一种良好的MEMS超级电容器电极材料。     

石墨烯/纳米减反结构复合透明导电薄膜的研究

石墨烯具有较高的透过率及良好的电导率, 作为透明导电薄膜具有潜在的应用价值。首先在石英基底上引入SiO₂纳米球阵列结构作为光学减反射层, 使石英基底可见光区光学透过率从93.2%增加到99.0%。然后利用常压化学气相沉积方法, 通过基底表面铜颗粒远程催化碳源, 直接在减反层上可控制备具有石墨烯/纳米减反结构的新型复合透明导电薄膜。通过去除SiO₂纳米球阵列结构形成反相复制的石墨烯空心球阵列结构, 且生长时间10 min时, 对应半高宽约40 cm^-1, I_2D/I_G = 2.31, I_D/I_G = 0.77, 证明在SiO₂纳米球阵列减反结构上制备了低缺陷且连续的全包覆少层石墨烯薄膜。引入SiO₂纳米球阵列减反结构后, 其在可见光区光学550 nm波长处的透过率平均提高了5.5%, 方块电阻相对无减反射层基底平均降低了20.09%。本研究方法避免了复杂的转移工序, 减少了对石墨烯的损失与破坏, 同时实现了高透光性及高导电性的功能协同, 在光伏器件、平板显示等领域展示出更大的应用前景。     

ZrO2-SiO2薄膜对离子交换增强玻璃的光学和力学性能影响

采用溶胶-凝胶法在玻璃表面制备出ZrO₂-SiO₂薄膜, 然后通过离子交换形成镀膜增强玻璃, 研究了薄膜组成对离子交换增强玻璃的力学和光学性能的影响。利用紫外可见分光光度计、激光椭偏仪、纳米压痕、三点抗弯和能谱(EDX)分析了薄膜结构及性能。结果表明: 所有薄膜均连续均匀, 纯ZrO₂薄膜为四方相结构, 含Si薄膜为无定形结构; 薄膜具有较高弹性恢复率(>60%)以及H/E比(>0.1), 有利于强度增强; 随Si含量增加, 可见光透过率增大, 但表面硬度和杨氏模量随之降低; 0.5ZrO₂-0.5SiO₂薄膜综合性能最佳: 表面硬度为18 GPa, 抗弯强度为393 MPa, 厚度~45 nm时可见光透过率大于85%。     

Preparation of strontium titanate thin films by mirror-confinement-type electron cyclotron resonance plasma sputtering

Using mirror-confinement-type electron cyclotron resonance (ECR) plasma sputtering method, strontium titanate (SrTiO₃) thin films have been prepared on Si and Pt/Ti/SiO₂/Si substrates at a low substrate temperature (below 450 K) in a low pressure (2.7×10⁻² Pa) environment of pure Ar and Ar/O₂ mixture. Prepared film surfaces were very smooth regardless of high deposition rate (8.5 nm/min). The composition ratio Sr/Ti of Sr to Ti in the films varied with the distance between the target and the substrate. All as-deposited films on Si substrates were found to be amorphous and were crystallized by post-deposition annealing using an electric furnace at 650 K, i.e. approximately 250 K lower than annealing for films obtained by conventional RF magnetron sputtering. Post-deposition annealing of these films using millimeter-wave radiation decreased the crystallization temperature to a value of 550 K. Furthermore, all as-deposited films on Pt/Ti/SiO₂/Si substrates by a plasma of Ar and O₂ gas mixture were found to be crystallized regardless of no substrate heating.     

Grain Refining and Decoupling in FePt/SiO2 Nanogranular Films for Magnetic Recording

FePt/SiO₂ nanogranular thin films have been prepared by molecular-beam epitaxy system on MgO (001) substrates with the method of insertion dual SiO₂ layers into Fe/Pt multilayer films. We report the relationships between the inserting thickness of SiO₂ layers and the microstructural and magnetic properties of FePt thin films. It indicated the nanogranular FePt thin films were successfully formed by inserting amorphous SiO₂ layers into the Fe/Pt films. The reduction of grain/domain size and isolation of FePt particles can be achieved by such insertion and maintain (001) texture. The average grain size of FePt films with 5-nm SiO₂ insert layers is estimated to be around 8 nm, while domain rotation is enhanced depicting a decoupling of intergrain interaction. The isolated grains are less magnetically coupled in the rotation mode and the reversal of magnetization is more independent     

Crystallization behavior and domain structure in textured Pb(Zr0.52Ti0.48)O3 thin films by different annealing processes

Amorphous Pb(Zr_0.52Ti_0.48)O₃ (PZT) thin films were prepared on the Pt/Ti/SiO₂/Si substrates by radio-frequency magnetron sputtering at room temperature. After rapid thermal annealing (RTA) and conventional furnace annealing (CFA) at different temperatures, the films were transformed into polycrystalline PZT thin films with (111) and (100) orientation, respectively. The phase formation and ferroelectric domains correlated with different orientation were systematically investigated by X-ray diffraction and piezoresponse force microscopy. The results showed that the perovskite PZT crystal with [111] orientation hetero-nucleated preferentially on top of the PtPb intermetallic phase at the PZT/Pt interface during RTA process. It is of interest to find that the domain self-organized into a structure with rounded shape at the early stage of crystallization. While the nucleation of the films treated by CFA dominantly homo-nucleated, thus the (100) orientation grains with minimum surface energy were easy to grow. The texture effects on ferroelectric properties of PZT films were also discussed in relation to the domain structure.     

PdSe2半导体薄膜的真空硒化法制备研究

PdSe2薄膜主要通过机械剥离法和气相沉积法制得,本研究采用一种简单有效的可在SiO2/Si衬底上制备PdSe2薄膜的方法.通过高真空磁控溅射技术在SiO2/Si衬底上沉积一层Pd金属薄膜,将Pd金属薄膜与Se粉封在高真空的石英管中并在一定的温度下进行硒化,获得PdSe2薄膜.根据截面高分辨透射电镜(HRTEM)照片可...     

Polycrystalline AlN films with preferential orientation by plasma enhanced chemical vapor deposition

AlN thin films for acoustic wave devices were prepared by Microwave Plasma Enhanced Chemical Vapor Deposition under different process conditions, employing Si (100) and Pt (111)/SiO₂/Si (100) substrates. The films were characterized by X-ray diffraction, Fourier transform infrared transmission spectroscopy, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. The values of the distance between the plasma and the tri-methyl-aluminum precursor injector, the radiofrequency bias potential, and the substrate temperature were central in the development of polycrystalline films. The choice of the chamber total pressure during deposition allowed for the development of two different crystallographic orientations, i.e., <0001> or <1010>. The film microstructures exhibited in general a column-like growth with rounded tops, an average grain size of about 40 nm, and a surface roughness lower than 20 nm under the best conditions.     

Deposition and dielectric properties of CaCu3Ti4O12 thin films on Pt/Ti/SiO2/Si substrates using pulsed-laser deposition

CaCu₃Ti₄O₁₂ (CCTO) thin films were successfully deposited on Pt/Ti/SiO₂/Si(1 0 0) substrates using pulsed-laser deposition technique. The crystalline structure and the surface morphology of the CCTO thin films were greatly affected by the substrate temperature and oxygen pressure. Thin films with a (2 2 0) preferential orientation were obtained at the substrate temperature above 700 °C and oxygen pressure above 13.3 Pa. The 480-nm thin films deposited under 720 °C and 26.6 Pa have a fairly high dielectric constant of near 2000 at 10 kHz and room temperature. The values of the dielectric constant and loss and their temperature-dependence under different frequency are comparable with those obtained in the epitaxial CCTO films grown on oxide substrates.     

Micro-scratch analysis and mechanical properties of plasma-deposited silicon-based coatings on polymer substrates

Advanced optical applications require multifunctional coatings with specific mechanical properties, such as resistance to damage and good adhesion to different types of substrates, including polymers. In the present study we deposited amorphous hydrogenated silicon nitride (SiN_1.3) and oxide (SiO₂) films on polycarbonate and on silicon substrates by plasma enhanced chemical vapor deposition (PECVD), using a dual-mode microwave/radio frequency plasma system. The film adhesion was determined by the micro-scratch test. Depth-sensing indentation and substrate curvature measurements were used to evaluate the microhardness. Young's modulus and residual stresses of the films. The adhesion strength, represented by the critical load, L_c, when the film starts to delaminate, was determined as a function of the substrate material and the energy of bombarding ions. A direct correlation between the L_c values and the mechanical properties of the films was found. The formation of different crack patterns in the coatings during the scratch procedure is explained in terms of stress release mechanism depending on the mechanical properties of the film, the substrate and the interface region. In addition, different models applicable to the evaluation of the work of adhesion in the case of hard coatings on soft substrates are critically reviewed.     

Structural, dielectric and optical properties of Ba(Ti, Zr)O3 thin films prepared by chemical solution deposition

Ba(Ti_0.95Zr_0.05)O₃ (BTZ) thin films grown on Pt/Ti/SiO₂/Si(100) substrates were prepared by chemical solution deposition. The structure and surface morphology of BTZ thin films has been studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). At 100 kHz, the dielectric constant and dissipation factor of the BTZ film are 121 and 0.016, respectively. The ellipsometric spectrum of the BTZ thin film annealed at 730 °C was measured in the range of wavelength from 355 to 1700 nm. Assuming a five-layer model (air/surface roughness layer/BTZ/interface layer/Pt) for the BTZ thin films on platinized silicon substrates, the optical constant spectra (refractive index n and the extinction coefficient k) of the BTZ thin films were obtained.