基于石墨烯/PDMS介质层的柔性压力传感器

提出了一种以石墨烯/PDMS为介质层的柔性压力传感器,主要介绍了石墨烯/PDMS介质层和柔性压力传感器的制备方法,研究了石墨烯浓度和石墨烯/PDMS介质层厚度对传感器灵敏度的影响。利用压力机和阻抗分析仪对柔性压力传感器进行了测试,结果表明柔性压力传感器有大的工作范围(0～20 kPa)和高的灵敏度(在0～3 kPa的灵敏度为0.3 kPa~(-1),3～8 kPa的灵敏度为0.06 kPa~(-1),8～20 k Pa的灵敏度为0.017 kPa~(-1));同时传感器的可恢复性和重复性能良好,可灵敏地检测手指的弯曲,在机器人皮肤和智能穿戴领域有着广阔的应用前景。     

高性能激光诱导石墨烯压力传感器的研究

为了保证在低成本、易制备的前提下提高激光诱导石墨烯压力传感器的性能,设计了一种石墨烯压力传感器的放大结构。表征了激光诱导石墨烯压力传感器的表面结构,分析了表面多孔泡沫结构对压阻效应的影响,采用COMSOL软件对传感器放大结构的受力情况进行仿真分析,得到在外界压力下石墨烯层的受力情况。选用3D打印方法制备树脂材料放大结构基底,在低成本的同时兼顾了轻质、高精度、高机械强度等性能。测试结果表明,压强在5～20 kPa范围内时,该放大结构的灵敏度较无放大结构提高了约43%。     

基于纳米孔结构的超高压石墨烯压力传感器设计

设计了一种基于纳米孔结构的超高压石墨烯压力传感器。由于氮化硼的六方晶体结构与石墨烯的晶体结构高度相似，该传感器采用氮化硼/石墨烯/氮化硼的石墨烯复合异质敏感薄膜作为压力传感器的敏感材料，利用石墨烯薄膜材料的压阻效应对压力进行检测。为保证传感器在400 MPa的压力载荷下对压力精准的检测，采用数学理论模型计算出不同孔径的纳米孔上石墨烯复合异质薄膜的应变大小，通过有限元仿真软件对石墨烯圆形薄膜的压力进行仿真，得到了圆形薄膜的最优半径。可为超高压石墨烯压力传感的结构设计和性能优化提供一定参考。     

基于MEMS技术的颅压监测传感器的设计与制备

颅内压力的监测对颅内疾病的诊断和治疗有重要的作用,基于硅的压阻效应,设计了一种可用于人体颅内压力监测的植入式压力传感器。根据压阻效应原理和薄板变形理论,完成了颅压传感器力学结构和电学性能的设计,然后采用微电子机械系统(MEMS)加工工艺完成了敏感芯片的制备,并提出了一种具有生物兼容性的绝缘封装结构。同时搭建了绝缘性测试平台和性能测试平台,通过测试证明封装后的传感器具有良好的绝缘性和抗渗透能力,且其灵敏度可达到1.608 mV/kPa,可对颅压的变化做出响应,为颅压传感器的批量化生产奠定了研究基础。     

基于石墨烯压阻效应的压力传感器研究进展

与传统的硅阻型压力传感器、陶瓷型压力传感器相比,石墨烯压力传感器具有测量灵敏度更高、测量范围更广的优点。对几种石墨烯压力传感器的研究进展进行综述。根据制作工艺的不同,将石墨烯压力传感器分为单层型和多层型。根据两大类型,列举最近六种石墨烯压力传感器的基本制作过程和测量范围、检测灵敏度等特性。根据六种石墨烯压力传感器的对比结果,得到单层型与多层型石墨烯压力传感器的不同工作特性及应用环境。针对单层型和多层型石墨烯传感器,分别提出提高性能的可行方案,对此类传感器的实际应用与推广具有一定的指导意义。     

三维弹性、轻质碳骨架复合气凝胶的制备及其应用

智能产业的飞速发展带动了对轻量化、高灵敏、快响应传感器的需求,然而复杂的材料组成和制备工艺阻碍了其实际应用。开发了一种基于三维碳纳米纤维(CNF)/还原氧化石墨烯(rGO)复合气凝胶的压阻式压力传感器,采用冰模板法和冻干技术使其成型,通过改变聚丙烯腈(PAN)/氧化石墨烯(GO)配比以及碳化温度调控复合气凝胶的导电性和压力灵敏度。当PAN纳米纤维和GO质量比为1∶1、碳化温度为400℃时,其压力传感灵敏度最高,在0～8 kPa和8～21 kPa的范围内分别为0.336和0.183 kPa^-1。另外,该压力传感器在不同大小压力、不同压缩频率和长时间压缩循环下还表现出了优异的稳定性。这种轻质、弹性的气凝胶传感器为高性能电子器件的快速制备提供了新思路,在健康管理、运动检测、人机交互等方面具有广泛的应用前景。     

仿生微结构柔性电容传感器设计及其性能研究

对柔性压力传感器进行了设计和研究，总体采用三明治式结构，介质层选择了复眼微结构的设计方式，电极层则需要在改性后的PDMS表面溅射一层金属银。将制备的三层结构通过键合的方式组成响应速度和灵敏度均较高的传感器。该传感器的测试结果为：当传感器表面压力一定时，复眼结构的电容式压力传感器的灵敏度达到了0.32 kPa-1，响应时间和恢复时间分别为130ms和120ms，迟滞性参数均小于7％，经过12000次的撞击实验，传感器仍然能保持稳定的输出。制备的传感器具有较强的响应特性、良好的恢复性和稳定性，能够适应柔性可穿戴电子器件的应用需求。     

高性能可穿戴式柔性压力传感器的制作与检测

对柔性压力传感器进行了设计和研究，总体采用三明治式结构，介质层选择了复眼微结构的设计方式，电极层则需要在改性后的PDMS表面溅射一层金属银。将制备的三层结构通过键合的方式组成响应速度和灵敏度均较高的传感器。该传感器的测试结果为：当传感器表面压力一定时，复眼结构的电容式压力传感器的灵敏度达到了0.32 kPa-1，响应时间和恢复时间分别为130ms和120ms，迟滞性参数均小于7％，经过12000次的撞击实验，传感器仍然能保持稳定的输出。制备的传感器具有较强的响应特性、良好的恢复性和稳定性，能够适应柔性可穿戴电子器件的应用需求。     

石墨烯/PDMS仿生银杏叶微结构柔性压阻式压力传感器

柔性压阻式压力传感器是可穿戴健康监测系统和人机交互设备的重要组成部分。在实际应用中,对具有高灵敏度和宽线性范围的压阻式压力传感器的需求迫切。以石墨烯油墨为功能层、聚二甲基硅氧烷(PDMS)为柔性材料,设计并制备了具有仿生银杏叶微结构的柔性压力传感器。利用扫描电子显微镜(SEM)表征了传感器的表面形貌。结果表明,仿生银杏叶表面的微结构包括平行叶脉和各种形状不一的凸起。该传感器具有1.56 kPa~(-1)的高灵敏度和22.6 Pa～20 kPa的宽线性范围,当施加不同的载荷时有明显的台阶现象,并且可以在10 000次的循环压力测试下保持稳定良好的性能。传感器的响应时间缩短至80 ms左右。此外,该压阻式压力传感器可用于检测人体关节的运动,表明其在健康监测和电子皮肤中应用潜力巨大。     

基于微纳光纤模式干涉仪和石墨烯薄膜的氨气传感器

将单锥微纳光纤模式干涉仪和石墨烯相结合,实现了一种高灵敏度的光纤式氨气传感器,其利用石墨烯的特异性吸附效应及微纳光纤结构的高灵敏度传感特性,通过检测干涉光谱的漂移量实现了对氨气浓度微弱变化的检测.对不同组传感器进行了对比分析,结果表明当光纤直径为3.4μm时最大检测灵敏度为10.8 pm/ppm,与文献中采用其它光纤结构所报道的结果相比几乎提高了一倍.该传感器具有结构简单、易于实现及灵敏度高等优点,在危害气体浓度报警和人体健康检测等领域有潜在的应用前景.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.