葡萄糖传感器与钾离子选择电极的集成

用微机械加工技术制备了微型葡萄糖传感器和钾离子选择电极并将它们集成于同一芯片上。本文设计的锥形微腔陈列结构提供了大批量生产多功能集成生物和化学传感器的可能性。     

MEMS三维微力探针传感器设计及性能测试

设计了一种基于压阻效应的微机电系统(MEMS)三维微力探针传感器并对其进行了性能测试.传感器传感单元采用四梁支撑结构,接触探针采用台阶式石英光纤,使传感器的抗干扰能力和灵敏度得到了显著的提高.设计了传感器的过载保护单元,传感器整体尺寸为4 mm×4 mm×16 mm.利用三维超精密定位平台与分析天平搭建传感器测试平台,对三维微力传感器进行性能测试.测试结果表明,该传感器灵敏度优于0.010 6 mV/μN,分辨率优于3μN,非线性误差优于传感器满量程的0.94%.因此,该传感器具有体积小、成本低、灵敏度高、抗干扰能力强、线性好、分辨率高的特点,在微力测试领域拥有广阔的应用前景.     

基于ZnO复合材料的芯片式pH和温度传感器

可穿戴传感器可以方便地监测汗液pH、体表温度等信号, 以此判断人体的健康状况, 因而吸引了广泛注意。本研究制备了一种用于检测人体皮肤表面温度及汗液pH的芯片式传感器。pH传感器为ZnO/聚苯胺(PAni)微纳米结构, 在不同pH溶液中的表面电位不同, 灵敏度达120 mV/pH。温度传感器为ZnO/还原氧化石墨烯(rGO)复合材料, 用简单的滴落涂布法在聚对苯二甲酸乙二醇酯/氧化铟锡(PET/ITO)导电电极表面修饰一层ZnO/rGO。随着温度的升高, ZnO/rGO复合材料的电阻下降, 其电阻变化量的灵敏度达-0.67%/℃。两种传感材料可以集成在一个微小的芯片上, 获得的多功能传感器表现出较高的稳定性, 在皮肤表面pH和温度检测方面具有潜在的应用价值。     

微腔阵列式多功能生物传感器

报导了谷氨酸、半乳糖集成传感器的制造和表征。传感器建立在硅衬底上用各向异性腐蚀制成的锥形微腔阵列上,不同酶膜沉积在相应的微腔中。采用这种结构可生产多功能的生物传感器。     

垂直耦合悬空型氮化硅微盘光学传感器

提出了一种垂直耦合型悬空氮化硅微盘谐振型传感器,该传感器由一个底部非悬空的接入波导和一个顶部悬空的微盘腔组成,并用实验证明了其具有较高的器件灵敏度和良好的机械稳定性。对于半径40μm的微盘,在1548. 98 nm谐振波长下可以实现超过104的品质因数以及大小适中、5. 66 nm的自由光谱范围。该传感器的灵敏度可通过覆盖不同的有机液体来测量,实验测得值约为554 nm/RIU。该三维传感器的制备与传统的光刻工艺相兼容,利于大批量低成本生产,同时凭借器件尺寸小、工艺简单、检测灵敏度高、响应快、免标记等特点,在国防安全、生物检测和环境监测等方面具有广阔的应用前景。     

用于氨氮检测的无透气膜安培型氨气微传感器及系统

设计并制备了一种无透气膜的安培型氨气微传感器,并构建了氨氮检测系统,该系统实现了将溶液中的氨氮转化为氨气,并应用所设计的微传感器检测气态氨氮．采用MEMS工艺制备组成该微传感器的微电极芯片,氨敏感材料选用铂黑,通过电化学方法修饰于微电极表面．在微电极芯片的SU-8微池中滴入微量LiCl溶液,形成可使氨气迅速扩散到电极表面的薄层电解液．使用自行设计的氨氮检测系统对不同浓度氨氮样品进行检测,对微传感器的时间响应特性、线性度、灵敏度及重复性进行了测试和分析．微传感器的线性范围为0．2mg／L～4mg／L,线性相关系数为0．9847,检测下限为0．2mg／L,达到90％响应信号所需的时间在3min以内．结果表明,使用安培型氨气微传感器检测氨氮的方法是可行的．     

离体电生理检测微电极阵列传感器的设计与制备(英文)

针对动物离体组织电生理检测的实际需求,设计并制备了一种以载玻片为基底,以微电极阵列为敏感元件,并将灌流装置集成一体的传感器芯片.采用微电子机械系统(MEMS)技术中的薄膜工艺完成了微电极阵列的制备,其导电层和绝缘层分别是铂和氮化硅.采用聚二甲基硅烷(PDMS)浇铸制成埋有管道的方形灌流槽.该传感器可保持离体组织的生理活性,同时实现电生理信号的64通道同步记录.整个芯片结构紧凑,接口简单,使用方便.对芯片的电学性能进行了研究,结果表明,通过在微电极表面电镀修饰铂黑,可有效降低其交流阻抗,提高信噪比.     

基于平面环形微腔结构的超高灵敏度位移传感器的研究

以平面环形微腔结构为核心器件,基于量子力学的隧道效应和“参量振荡不稳定”效应,结合理论计算及ANSYS和Beamprop仿真,设计出基于环形微腔结构的超高灵敏度位移传感器,特别是在1．55μm的谐振波下,对所设计的位移传感器进行了ANSYS力学仿真、Beamprop传输特性仿真以及输出特性数值模拟,论证了位移传感器的可行性,并为以后的实验奠定了基础。     

新型力平衡微机械真空传感器研究

力平衡微机械真空传感器采用 ｐ＋＋硅自停止腐蚀技术和硅／玻璃键合技术制作,为了保持参考腔处在高真空状态,使用非蒸散吸气剂来吸附参考腔中的残余气体。研制了两种结构新型力平衡真空传感器,结果表明,采用力平衡模式工作可以扩展传感器的动态范围,灵敏度高。对力平衡电压与真空度的关系进行了研究,理论值与实测值符合得非常好。     

基于分子印迹技术的尿素仿生微传感器

设计了基于分子印迹与电化学微传感器的尿素仿生微传感器,采用MEMS工艺制作集成微型3电极系统,实现了传感器的微型化.通过电化学方法制备了分子印迹聚合物(MIP),印证了分子印迹聚合物的印迹效果.比较了3支传感器的响应曲线,得到了相近的灵敏度,灵敏度在0.10μA/(μmol.L-1)左右,线性度达到了0.95,检测下限为1.00μmol/mL,分析尿素溶液的标准偏差小于5%,达到和接近临床分析要求,为生物传感器向仿生生物传感器发展进行了具有临床意义的尝试.     

Cross-correlation of optical microcavity biosensor response with immobilized enzyme activity. Insights into biosensor sensitivity

Porous silicon multilayer structures have remarkable optical and morphological properties that can be exploited for biosensing. In particular, a high internal surface area (>100 m(2)/cm(3)) and a linear response profile to changes in the dielectric environment enable fabrication of sensitive devices and a straightforward quantitation of the optical response. These essential operating characteristics are illustrated for p+ mesoporous silicon (pore diameter 15-20 nm) optical microcavities. A series of devices were prepared to permit the immobilization of glutathione-S-transferase ( approximately 50 kDa) within the porous matrix. Enzyme activity was exploited as an indirect means to quantitate the amount of protein immobilized. Activity was positively correlated with the optical sensor response. However, at high enzyme load the activity becomes nonlinear while the microcavity response remains linear. These data were used to determine the transduction limit (minimum amount of protein required to transduce an optical response), which is reported as areal mass sensitivity ranging between 50 and 250 pg/mm(2). This value is considered in context with the dynamic range of the bulk sensitivity, defined as the magnitude of the wavelength shift per refractive index unit, which was measured as a function of microcavity design parameters. This work has uncovered key parameters that can be tuned to improve the detection limit of this sensor modality. Because of the ever increasing number of emerging new biosensor technologies, defining sensor detection limits has become an ambiguous topic and a need exists to standardize measurements and sensitivity units. For chip-based devices, it seems appropriate to report sensitivity in terms of the minimum number of grams of bound target per surface area.     

High‐Quality,Ultraconformal Aluminum‐Doped Zinc Oxide Nanoplasmonic and Hyperbolic Metamaterials

Aluminum‐doped zinc oxide (AZO) is a tunable low‐loss plasmonic material capable of supporting dopant concentrations high enough to operate at telecommunication wavelengths. Due to its ultrahigh conformality and compatibility with semiconductor processing, atomic layer deposition (ALD) is a powerful tool for many plasmonic applications. However, despite many attempts, high‐quality AZO with a plasma frequency below 1550 nm has not yet been realized by ALD. Here a simple procedure is devised to tune the optical constants of AZO and enable plasmonic activity at 1550 nm with low loss. The highly conformal nature of ALD is also exploited to coat silicon nanopillars to create localized surface plasmon resonances that are tunable by adjusting the aluminum concentration, thermal conditions, and the use of a ZnO buffer layer. The high‐quality AZO is then used to make a layered AZO/ZnO structure that displays negative refraction in the telecommunication wavelength region due to hyperbolic dispersion. Finally, a novel synthetic scheme is demonstrated to create AZO embedded nanowires in ZnO, which also exhibits hyperbolic dispersion.     

Surface-plasmon-resonance-based fiber-optic refractive index sensor: sensitivity enhancement

We have experimentally studied the surface plasmon resonance (SPR)-based fiber-optic refractive index sensor incorporating a high-index dielectric layer using the wavelength interrogation method. Silver and gold have been used as SPR active metals followed by a high-index dielectric layer of silicon. Experimental results predict a redshift in the resonance wavelength with the increase in the refractive index of the sensing layer for a given thickness of the silicon layer. Further, as the thickness of the silicon layer increases, the sensitivity of the sensor increases. The upper limit of the silicon film thickness for the enhancement of the sensitivity has been found to be around 10 nm. The experimental results obtained on sensitivity match qualitatively with the theoretical results obtained using the N-layer model and the ray approach. The increase in sensitivity is due to the increase in the electric field intensity at the silicon-sensing-region interface. In addition to an increase in sensitivity, the silicon layer can be used to tune the resonance wavelength and can protect the metal layer from oxidation and hence can improve the durability of the probe.     

Low temperature silicon nitride by hot wire chemical vapour deposition for the use in impermeable thin film encapsulation on flexible substrates

High quality non porous silicon nitride layers were deposited by hot wire chemical vapour deposition at substrate temperatures lower than 110 degrees C. The layer properties were investigated using FTIR, reflection/transmission measurements and 1:6 buffered HF etching rate. A Si-H peak position of 2180 cm(-1) in the Fourier transform infrared absorption spectrum indicates a N/Si ratio around 1.2. Together with a refractive index of 1.97 at a wavelength of 632 nm and an extinction coefficient of 0.002 at 400 nm, this suggests that a transparent high density silicon nitride material has been made below 110 degrees C, which is compatible with polymer films and is expected to have a high impermeability. To confirm the compatibility with polymer films a silicon nitride layer was deposited on poly(glycidyl methacrylate) made by initiated chemical vapour deposition, resulting in a highly transparent double layer.     

Single and Double Fabry–PÉrot Structure Based on Porous Silicon for Chemical Sensors

This paper presents sensing of chemicals using porous silicon as optical sensor fabricated by periodically modulating the porosity of silicon to produce multilayered structures. Single and double Fabry-Perot (FP) structure is designed by using electrochemical anodical etching technique. The operation of chemical sensor is based on the change of effective refractive index of the porous silicon medium, induced by condensation of solvent vapors around the pillars. Resonant wavelengths of single and double multilayer with a microcavity have presented a red shift when exposed to vapor of solvents. On the other hand, resonant wavelength of double FP structure sandwiched with a diffusion layer has presented different optical response when exposed to vapor of solvents. This structure actually has two stop bands with two resonant wavelengths. While of the beginning first and second stop band and resonant wavelength shift together to the infrared region continuously, after awhile second stop band stopped but the first stop band continued to shifting to the infrared region. Time dependence of optical response of proposed structure can be used for identification chemicals.     

Broadband and efficient wavelength conversion in a slot-width switching silicon–organic hybrid waveguide

We propose a slot-width switching (SWS) silicon–organic hybrid waveguide for broadband and efficient wavelength conversion. By switching the slot width of different lengths, the quasi-phase-matching can be obtained. Compared with width-modulated silicon-on-insulator (SOI) waveguide, the non-linear absorption can be ignored in slot waveguide which is filled with p-toluene sulphonate. Consequently, the conversion efficiency at a particular signal wavelength is improved, and the 3-dB conversion bandwidth is also extended. The numerical simulation results indicate that, for a continuous-wave pump at 1550 nm, a conversion bandwidth of 570 nm and a peak conversion efficiency of 11.32 dB can be realized in a 7.5-mm-long SWS waveguide, which is better than that of width-modulated SOI waveguide.     

Liquid crystal infiltrated photonic crystal fibers for electric field intensity measurements

The application of nematic liquid crystal infiltrated photonic crystal fiber as a sensor for electric field intensity measurement is demonstrated. The device is based on an intrinsic sensing mechanism for electric fields. The sensor probe, which consists of a 1 cm infiltrated section of photonic crystal fiber with a lateral size of ～125 μm, is very compact with small size and weight. A simple all-fiber design for the sensor is employed in an intensity based measurement scheme. The transmitted and reflected power of the infiltrated photonic crystal fiber is shown to have a linear response with the applied electric field. The sensor is operated in the telecommunication window at 1550 nm. The temperature dependence of the device at this operating wavelength is also experimentally studied and discussed. These structures can be used to accurately measure electric field intensity and can be used for the fabrication of all-fiber sensors for high electric field environments as both an in-line and reflective type point sensor.     

Bloch surface wave structures for high sensitivity detection and compact waveguiding

Resonant propagating waves created on the surface of a dielectric multilayer stack, called Bloch surface waves (BSW), can be designed for high sensitivity monitoring of the adjacent refractive index as an alternative platform to the metal-based surface plasmon resonance (SPR) sensing. The resonant wavelength and polarization can be designed by engineering of the dielectric layers unlike the fixed resonance of SPR, while the wide bandwidth low loss of dielectrics permits sharper resonances, longer propagation lengths and thus their use in waveguiding devices. The transparency of the dielectrics allows the excitation and monitoring of surface-bound fluorescent molecules. We review the recent developments in this technology. We show the advantages that can be obtained by using high index contrast layered structures. Operating at 1550 nm wavelengths will allow the BSW sensors to be implemented in the silicon photonics platform where active waveguiding can be used in the realization of compact planar integrated circuits for multi-parameter sensing.     

Design of all-optical tunable filter based on two-dimensional photonic crystals for WDM (wave division multiplexing) applications

In this paper, all-optical tunable filters based on two-dimensional photonic crystals with very small dimensions for optical telecommunication of WDM technology are designed and simulated. The structure is made of air holes in a dielectric background. The tuning is done by changing resonant defect angle. The channels obtained for this structure will be set in wavelength range of 1550 nm. Created channels are at wavelengths of 1550, 1551, 1552, and 1565 (16 channels); the distance between adjacent channels is 1 nm. Design and simulation of this filter is done by RSOFT software. Quality factor, transmission efficiency, and band gap shows that filter performance is very good.     

基于硅基定向耦合器的单纤三向器设计

设计了基于硅基二氧化硅定向耦合器的光纤到户单纤三向器。通过定向耦合器耦合系数对波长的信赖性,在相同的耦合长度下实现单纤三向器三个波长(1310nm,1490nm和1550nm)的全周期耦合或半周期耦合,使三个波长信号从不同的耦合臂输出,完成三向器粗分波功能。有限差分束传播法(FD-BPM)模拟结果表明三向器损耗小于0.5dB,三个响应波长的1dB带宽即可满足ITU.984带宽要求,最优串扰为-14dB。