基于层层自组装纳米碳管薄膜的应变传感器

以层层自组装单壁碳纳米管网状薄膜为敏感材料,在柔性基底上制作了应变传感器,并对薄膜和器件性能进行了测试。测试结果表明:薄膜组装均匀,电导性良好,电阻随组装层数增加呈指数态下降;器件对应变呈现较好的敏感特性、线性响应和可恢复性,灵敏度为4.25;通过添加防护层屏蔽外界湿度及光照影响,传感器稳定性显著提高。该传感器可用于弯曲表面的应力应变检测。     

Nitrogen dioxide gas sensors based on titanium dioxide thin films deposited on langasite

Conductometric sensors, based on pure and Au-doped TiO₂ thin films on langasite (LGS) substrates have been investigated for detecting low concentrations (510 ppb and 1060 ppb) of NO₂ in synthetic air at a temperature range between 220 °C and 320 °C. Thin films of TiO₂ were deposited using the radio frequency (RF) magnetron sputtering method. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were employed for the characterization of thin films. It was observed that the Au-doped TiO₂ sensor has fast response and recovery time of 10 and 29 s respectively towards 510 ppb of NO₂ at 273 °C.     

Micromachined piezoelectric force sensors based on PZT thin films

A micromachined lead zirconate titanate (PZT) force sensor for scanning force microscope (SFM) is conceptualized by its piezoelectricity. The fabrication procedure is interpreted, and mechanical characteristics of the micromachined PZT force sensors with various lengths are studied in this paper. A compact SFM is constructed by using the piezoelectric PZT sensor. A very clear image is taken by this SFM. The current study of the micromachined PZT force sensor can be considered as a breakthrough of design of SFM as well as a good example of integrated piezoelectric microdevices     

Optical and structural properties of NiMgO thin films formed by sol-gel spin coating

Ni_1−xMg_xO thin films across the full compositional range were formed by a low-cost sol-gel spin coating method. Optical transmission of the resultant films in the ultraviolet-visible spectral region increased to as high as 90% upon sintering, and X-ray diffraction verified an increase in crystallinity for sintering temperatures up to 1000 °C, with root mean square roughness below 1 nm when sintered between 600 and 800 °C. The lattice parameter of the rock salt Ni_1−xMg_xO films showed a linear shift with increased magnesium concentration, consistent with a Vegard's Law relationship between the two binaries. Optical energy gaps from 3.6 to > 6.5 eV were realized by adjusting the composition of the Ni_1−xMg_xO films, demonstrating the suitability of the ternary for optical devices in the UV-C spectral region.     

半导体陶瓷型薄膜气敏传感器的研究进展

半导体陶瓷型薄膜气敏传感器,具有灵敏度高、与气体反应快、制备成本较低等优点,已经成为近年传感器研究和开发的重点．是未来气敏传感器的发展方向之一。本文介绍了陶瓷型半导体薄膜气敏传感器常见的器件结构、薄膜材料的主要制备方法．部分主要的半导体金属氧化物薄膜气敏材料．以及近期相关的研究进展,并扼要分析了今后的发展方向。     

Optical properties of silver sulphide thin films formed on evaporated Ag by a simple sulphurization method

Silver sulphide (Ag₂S) thin films were grown on the surface of silver films (Ag) deposited on glass substrate by using a simple chemical sulphurization method. According to X-ray diffraction analysis, the Ag₂S thin films display low intensity peaks at 34.48°, 36.56°, and 44.28°, corresponding to diffraction from (100), (112) and (103) planes of the acanthite phase (monoclinic). A model of the type Ag₂S/Ag/glass was deduced from spectroscopic ellipsometric measurements. Also, the optical constants (n, k) of the system were determined. Furthermore, the optical properties as solar selective absorber for collector applications were assessed. The optical reflectance of the Ag₂S/Ag thin film systems exhibits the expected behavior for an ideal selective absorber, showing a low reflectance in the wavelength range below 2 µm and a high reflectance for wavelengths higher than that value. An absorptance about 70% and an emittance about 3% or less were calculated for several samples.     

Miniaturized implantable pressure and oxygen sensors based on polydimethylsiloxane thin films

We demonstrate the application of polydimethylsiloxane (PDMS) thin films in highly sensitive pressure and oxygen sensors, designed for pressure and oxygen content measurements within the heart and blood vessels. PDMS thin film displacement as a result of pressure changes was transduced by a capacitive detection technique to produce quantitative measurement of absolute pressures. Oxygen measurements were obtained by transducing the current change between a Pt and an Ag/AgCl electrode on a glass substrate, with KCl soaked filter paper as the electrolytic media that is separated from the oxygen carrying fluid by a thin PDMS membrane. The best sensitivity for the pressure sensor was ~ 0.1 nA/KPa, with a noise limited resolution of ~ 0.09 KPa. For the oxygen sensor, the best sensitivity was ~ 2.75 µA for 1% change in oxygen content of the surrounding media, with a noise limited resolution of ~ 6.18 ppm oxygen. These experimental results agree with theoretical modeling predictions, and suggest that the semi-permeable and biocompatible PDMS can be successfully adopted as the contacting membrane in an integrated sensor design to quantify pressure and oxygen content in blood.     

蒸发诱导自组装仿生合成高有序度三维六方介孔氧化硅薄膜

借鉴自然界生物矿化的形成机理,利用蒸发诱导自组装(EISA)的方法,以十六烷基三甲基溴化铵(CTAB)为结构导向剂,正硅酸乙酯(TEOS)为硅源,通过浸渍提拉在普通玻璃片上制备出高有序度、三维六方结构的介孔氧化硅薄膜,通过XRD、TEM、低温N2吸附/脱附等方法对薄膜进行了表征,并初步讨论了形成三维六方结构的机理.     

Fabrication of an a-IGZO thin film transistor using selective deposition of cobalt by the self-assembly monolayer (SAM) process

Interest in transparent oxide thin film transistors utilizing ZnO material has been on the rise for many years. Recently, however, IGZO has begun to draw more attention due to its higher stability and superior electric field mobility when compared to ZnO. In this work, we address an improved method for patterning an a-IGZO film using the SAM process, which employs a cost-efficient micro-contact printing method instead of the conventional lithography process. After a-IGZO film deposition on the surface of a SiO2-layered Si wafer, the wafer was illuminated with UV light; sources and drains were then patterned using n-octadecyltrichlorosilane (OTS) molecules by a printing method. Due to the low surface energy of OTS, cobalt was selectively deposited on the OTS-free a-IGZO surface. The selective deposition of cobalt electrodes was successful, as confirmed by an optical microscope. The a-IZGO TFT fabricated using the SAM process exhibited good transistor performance: electric field mobility (micro(FE)), threshold voltage (V(th)), subthreshold slope (SS) and on/off ratio were 2.1 cm2/Vs, 2.4 V, 0.35 V/dec and 2.9 x 10(6), respectively.     

Fabrication of graphene thin films based on layer-by-layer self-assembly of functionalized graphene nanosheets

In this study, we present a facile means of fabricating graphene thin films via layer-by-layer (LbL) assembly of charged graphene nanosheets (GS) based on electrostatic interactions. To this end, graphite oxide (GO) obtained from graphite powder using Hummers method is chemically reduced to carboxylic acid-functionalized GS and amine-functionalized GS to perform an alternate LbL deposition between oppositely charged GSs. Specifically, for successful preparation of positively charged GS, GOs are treated with an intermediate acyl-chlorination reaction by thionyl chloride and a subsequent amidation reaction in pyridine, whereby a stable GO dispersibility can be maintained within the polar reaction solvent. As a result, without the aid of additional hybridization with charged nanomaterials or polyelectrolytes, the oppositely charged graphene nanosheets can be electrostatically assembled to form graphene thin films in an aqueous environment, while obtaining controllability over film thickness and transparency. Finally, the electrical property of the assembled graphene thin films can be enhanced through a thermal treatment process. Notably, the introduction of chloride functions during the acyl-chlorination reaction provides the p-doping effect for the assembled graphene thin films, yielding a sheet resistance of 1.4 kΩ/sq with a light transmittance of 80% after thermal treatment. Since the proposed method allows for large-scale production as well as elaborate manipulation of the physical properties of the graphene thin films, it can be potentially utilized in various applications, such as transparent electrodes, flexible displays and highly sensitive biosensors.     

Optical and electrical properties of ZnO nanoparticle thin films deposited on quartz by sparking process

ZnO nanoparticle thin films were deposited on quartz substrates by a novel sparking deposition which is a simple and cost-effective technique. The sparking off two zinc tips above the substrate was done repeatedly 50-200 times through a high voltage of 10 kV in air at atmospheric pressure. The film deposition rate by sparking process was approximately 1.0 nm/spark. The ZnO thin films were characterized by X-ray diffraction, Raman spectroscopy, UV-vis spectrophotometry, and ionoluminescence at room temperature. The two broad emission peaks centered at 483 nm (green emission) and 650 nm (orange-red emission) were varied after two-step annealing treatments at 400-800 °C. Moreover, the electrical resistivity of the films was likely to be proportional to the peak intensity of the orange-red emission.     

Hall effect measurements in gas sensors based on nanosized Os-doped sol-gel derived SnO/sub 2/ thin films

The influence of dopants on the electrical properties of gas sensitive layers used in semiconductor gas sensors has to be carefully understood for getting a deeper insight in the relationship between the sensor performance and its chemical composition. In this work, undoped and Os-doped SnO/sub 2/ thin films have been prepared by the sol-gel process with an Os-Sn atomic ratio of 5%. The films have been characterized by resistivity and Hall effect measurements in a temperature range from 100 K to 500 K, both in air and in vacuum. The results have been investigated according to grain boundary scattering mechanism. We found that in air, the ambient oxygen species adsorbed on the film increase the height of the grain boundary barriers and the activation energy for the electrical conductivity increases in the doped film. In vacuum, the results showed that the height of the intergranular barrier is lower than the corresponding value in air. Both in air and in vacuum, the conductivity of the Os-doped sample is higher than the value in the undoped SnO/sub 2/ sample. The same occurs for the Hall mobility and the carrier concentration. The experimental results have been used to explain the better methane sensitivity, at low temperature, of the Os-doped films as compared with the undoped ones.     

静电自组装制备含苝衍生物的纳米层状复合膜

采用静电自组装方法制备了稳定的含苝衍生物纳米层状复合膜．用石英晶体微天平(QCM)对静电自组装过程进行了原位监控，发现组装次数与QCM频率变化呈线性关系，通过静电吸附得到的多层累积薄膜具有层状结构，X射线光电子能谱图上出现苝衍生物的特征峰表明组装的薄膜中含有苝衍生物．原子力显微镜表征结果表明，复合膜在一定程度上规整并且均匀的覆盖在电极表面，但存在分子团聚现象，将苝衍生物小分子溶解在聚电解质溶液中作混合浸渍液，提高了组装薄膜的稳定性．     

基于内埋光纤Bragg光栅传感器的复合材料固化过程监测

为了全面了解复合材料的固化特性,在对碳纤维增强树脂基复合材料固化变形进行数值仿真分析的基础上,将自行设计的光纤Bragg光栅（FBG）传感器埋入复合材料中,实时在线监测复合材料固化过程中温度和应变的演变。预浸料铺层方式为[0₁₁/90₁₁],分别在层合板0°和45°方向的典型位置埋入FBG温度和应变传感器,采用热模压方式固化成型复合材料层合板,并对成型后的层合板进行连续2次降温处理,实时记录固化过程中FBG传感器中心波长的变化。结果表明:在相同的温度条件下,复合材料在第1次降温初始阶段的压应变绝对值明显小于在第2次降温初始阶段的压应变绝对值,表明复合材料在第1次降温过程中仍在进行FBG传感器可检的“后固化”反应;此外,层合板变形的FBG传感器监测数据与有限元模拟结果吻合良好。因此,采用内埋FBG传感器的方法能够实时监测复合材料固化过程,为更全面地分析复合材料固化特性提供了一种可靠有效的方法。      

Some properties of GaSe thin films formed by the three-temperature method

Thin films of the semiconducting compound GaSe have been prepared by the three-temperature method (two-source vacuum evaporation) and deposited onto Pyrex substrates at temperatures between 230° and 290°C. Micrographs and X-ray diffraction analysis of the thin films have shown that they are poly-crystalline. The diffraction maxima have been indexed in terms of a hexagonal lattice of GaSe with unit cell dimensions $\text{a = 3.76}\text{A}\text{?}\text{and}\text{c = 15.95}\text{A}\text{?}$. Very strong and sharp 00l peaks indicate a highly preferred orientation of the crystallites with their c-axis normal to the plane of the film. The electrical resistivity versus temperature behaviour has revealed intrinsic conduction above 130°C with an activation energy equal to 1.88 eV. The optical energy gap value determined from transmission data has been found to be approximately 2.0 eV, which is close to the value obtained for a single-crystal specimen. The exciton peak found in the absorption spectrum of the GaSe single crystal at 2.002 eV is not present in the case of thin films.     

原位聚合 ( PSS/ PANI) n复合膜的静电层2层自组装

基于静电相互作用 , 从苯胺单体出发原位聚合、现场掺杂、层2层自组装制备多层聚苯乙烯磺酸钠( PSS) /聚苯胺 ( PANI) 复合膜。为了明确控制 PSS/ PANI复合膜纳米结构的因素 , 以紫外2可见 (UV2Vis) 光谱跟踪 PSS/ PANI复合膜的成膜过程 , 系统地研究了基片性质、 氧化剂用量及沉积时间等溶液因素对单个双层复合膜纳米结构的影响 , 得到了制备单个双层复合膜的较优条件。在此基础上变换苯胺单体浓度 , 制备了不同纳米结构的多层复合膜 ( PSS/ PANI) n, 并用原子力显微镜 (AFM) 、 扫描电镜 (SEM) 及椭偏仪等对该多层复合薄膜的形貌结构进行了表征。结果表明 , 通过控制沉积条件 , 每双层复合膜的厚度可控制在 40～100 nm , 电导率可达- 12. 675 mS·cm , 并且可制备增长均匀的 8 个双层的 ( PSS/ PANI) 8复合膜。热失重分析 ( TGA) 表明 , ( PSS/ PANI) n多层复合膜的热稳定性优于普通 PSS/ PANI复合膜。     

The dependence of hardness on the density of amorphous alumina thin films by PECVD

Smooth, uniform and transparent aluminum oxide films were deposited at low temperature (≤ 500°C) by r.f. plasma enhanced chemical vapor deposition (PECVD) with AlCl₃, H₂ and CO₂ as the reactants. The measurements of mechanical and optical properties demonstrate a potential application of PECVD aluminum oxide film as an optical protective coating. The variation of film hardness and density with deposition parameters is apparent and shows a similar dependence while the composition stoichiometry is not so influenced. For amorphous thin films incorporating hydrogen and/or microvoid with no apparent variation on composition stoichiometry, the film hardness is dominated by density and a function near linear can be constructed as energy density is taken into account as an apparent character of hardness.     

The preparation of amperometric xanthine sensors based on multilayer thin films containing xanthine oxidase

An amperometric xanthine biosensor was prepared by immobilizing xanthine oxidase (XOx) on the surface of a platinum (Pt) disk electrode. The Pt electrode was first covered with a polyelectrolyte multilayer (PEM) film composed of poly(allylamine hydrochloride) (PAH) and poly(vinyl sulfate) (PVS) to block the Pt surface from the access of uric acid, a reaction product of the XOx-catalyzed oxidation reaction of xanthine, because uric acid can be electrochemically oxidized on the Pt electrode to induce interference. The PEM film-covered Pt electrode was further modified with a XOx-containing multilayer film composed of XOx and poly(dimethyldiallylammonium chloride) (PDDA). The xanthine biosensors thus prepared can be used successfully for detecting xanthine in the concentration range of 3–300 μM. The output current of the sensors depended on the number of the XOx/PDDA layers in the film. The PAH/PVS layer was effective to eliminate the uric acid interference.     

催化条件对SiO2静电自组装薄膜光学性质的影响

用NH3·H2O催化和先后经HCl、NH3·H2O、HCl依次分步催化分别制备了SiO2溶胶.在低折射率的玻璃基片上用静电自组装(electrostatic selfassembly multilayer,ESAM)法制备了聚电介质PDDA与SiO2的光学增透薄膜.研究了制备SiO2溶胶的催化条件对SiO2的光学增透薄膜在可见光区透光特性的影响.用傅立叶红外光谱仪(FT-IR)、X光电子能谱(XPS)、透射电镜(TEM)对薄膜进行了组成和结构分析,用721分光光度计测试薄膜的透光性能.结果显示,两种薄膜都使基片的透过率得到大大增加.NH3·H2O催化SiO2溶胶制备的SiO2光学增透膜使基片在波长为520nm处透过率达到99.2%,相对于HCl与NH3·H2O分步催化制备的薄膜强,但薄膜的耐刮伤能力较相对较差.