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Micro & Nano Letters, IET

Issue 12 • Date December 2012

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Displaying Results 1 - 25 of 47
  • APCOT 2012 Special Issue [Editorial]

    Page(s): 1157
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (53 KB)  

    The sixth Asia-Pacific Conference on Transducers and Micro/Nano Technologies (APCOT 2012) was held between 4th and 7th of July in Nanjing, China. It was technically co-sponsored by IEEE Nanjing Section. Annually, the conference provides an opportunity for engineers from the diverse worlds of academia, industry and research institutions to share the latest developments in the field. The topics covered were similarly varied, ranging from sensor technology and microsystems (both physical and biological) to optical MEMS and nano devices. View full abstract»

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  • Metal-based piezoelectric energy harvesters by direct deposition of PZT thick films on stainless steel

    Page(s): 1158 - 1161
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (374 KB)  

    This study presents a lead zirconate titanate (PZT) energy harvester with stainless steel (SUS 304) substrate the resonance frequency of which is lower than 100 Hz. The PZT thick films had been directly and successfully deposited on SUS substrates by the sol-gel method with a thickness of 4 m. Then the deposited films were evaluated by the X-ray diffraction method and the scanning electron microscopy method. Energy harvesters were fabricated and their performance was measured under various vibration conditions. Optimal output power and resonant frequency are 15 W and 89 Hz, respectively, when the devices were tested under 1 g acceleration vibration and connected with a 23 kΩ resistor. View full abstract»

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  • Fabrication of flexible dye-sensitised solar cells with titanium dioxide thin films based on screen-printing technique

    Page(s): 1162 - 1165
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    Flexible dye-sensitised solar cells (FDSSCs) which have different quantities of arrayed titanium dioxide (TiO2) working electrode for parallel modules are introduced. FDSSCs are usually fabricated as a module type instead of single cell to enhance conversion efficiency and characteristic parameters. The general FDSSCs modules are designed as parallel strip-shaped and as parallel interconnection types, and there are some advantages such as easy fabrication, low cost and simple structure. In this reported study, the active areas of FDSSCs are the same (0.48 cm2), and they have different quantities of TiO2 thin films. The single strip-shaped TiO2 working electrode has a larger internal resistance than more quantities of TiO2 thin films. Therefore, and they have fabricating the different quantities of arrayed flexible TiO2 working electrodes is the better method to solve the problem, higher internal resistance than single TiO2 thin film. As a result, the FDSSC, which has the triple strip-shaped TiO2 working electrode, has a higher conversion efficiency (0.25%) than other different quantities of TiO2 thin films. View full abstract»

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  • Fabrication and tests of a three-dimensional microsupercapacitor using SU-8 photoresist as the separator

    Page(s): 1166 - 1169
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (326 KB)  

    Presented is a microsupercapacitor using SU-8 photoresist as the separator, featuring by high-aspect-ratio three-dimensional (3D) electrodes and high capacity per unit area. A scalable and mechanically stable structure for microsupercapacitors has been designed. By combining the preparation strategy for self-supporting nanoporous electrodes with micromachining technologies for high-aspect-ratio structures, 3D electrodes that allow for a heavy load of electrode material per unit area has been achieved. Electrochemical characterisation results of the prototype using ionic liquid as the electrolyte demonstrate that the microsupercapacitor exhibits a high specific energy of 330 mJcm-2 and a large specific capacitance of 160 mFcm-2, which are attributed to both the high-performance materials and the well-designed microstructure. This device can be potentially applied to various energy systems, such as electronic backup power supplies and microenergy storage devices. View full abstract»

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  • Microstructure and piezoelectric properties of AlN thin films grown on stainless steel for the application of vibration energy harvesting

    Page(s): 1170 - 1172
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (201 KB)  

    By analysing the energy flow in a piezoelectric generator, it was revealed that the mechanical factor, electromechanical coupling coefficient and dielectric loss of the generator have significant influence on its energy conversion efficiency. Based on this analysis, aluminium nitrate (AlN) thin films deposited on stainless steel (SUS) were selected to substitute lead titanate zirconate thin films deposited on single-crystal Si for fabricating miniature devices. These thin films were prepared with an electron cyclotron resonance sputtering system. The influences of the surface modification (polishing or coating a Pt/Ti thin layer) of SUS substrates on c-axis orientation, piezoelectric coefficient and effective coupling coefficient of AlN thin films were investigated. View full abstract»

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  • Development of microelectromechanical systems electromagnetic vibration energy scavengers with a nonlinear electroplated nickel spring

    Page(s): 1173 - 1175
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (342 KB)  

    Three electromagnetic vibration energy scavengers with electroplated Ni springs have been designed, fabricated and characterised. Prototype I consists of a coil, an Ni spring on a silicon frame and a permanent magnet. Prototypes II and III are with a sandwich structure and consist of two coils, an Ni spring and a permanent magnet. There are air channels in the silicon frame in prototype III. These prototypes were fabricated using microelectromechanical systems microfabricating techniques. The experimental results show the electroplated Ni spring is a nonlinear and hardened one, so the spring-magnet system has a different resonant frequency under different excited vibration. The tested results show that prototype III has the highest output voltage and output power. The maximal load voltage is 157.5-mV and the maximal load power is 21.7--W for prototype III when it is excited by vibration with 280.9-Hz frequency and 0.8-g acceleration. View full abstract»

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  • Micro cobalt electrodes for detection of total phosphorus in water

    Page(s): 1176 - 1179
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (349 KB)  

    In this study, the characterisation and calibration of microfabricated cobalt electrodes for the detection of total phosphorus (TP) in water are presented. The microelectrode chips were fabricated by microelectromechanical systems technology, and cobalt was used as the sensing material modified on the surface of microelectrodes using the electrodepositing method. The surface morphology and crystal direction of modified cobalt were examined and the electrochemical characterisation of cobalt electrodes was performed. The cobalt microelectrode showed good linear response to phosphate in the range of 10-6-10-2 M/l with the slope of about 28 mV/dec. The microelectrodes also presented good stability, consistency and reproducibility. These electrodes were applied to detect TP concentration in water samples from a lake. Calibration was performed for each electrode before the test. The test result using these cobalt microelectrodes was consistent with the concentration given in the certificate of qualified water of the quality detection institute. View full abstract»

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  • Absolute micro pressure measurements based on a high-overload-resistance sensor

    Page(s): 1180 - 1183
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (349 KB)  

    Presented is a piezoresistive absolute micro pressure sensor, which is of great benefit for altitude location. In this investigation, the design, fabrication and testing of the sensor are carried out. By analysing the stress distribution on sensitive elements using the finite-element method (FEM), a novel structure through the introduction of beams into the standard bossed diaphragm is built up. The proposed configuration presents its advantages in terms of sensitivity and overload resistance compared with the standard bossed diaphragm and conventional plane diaphragm structures. The sensor is fabricated based on silicon bulk micromachining technology, and the detailed processing program is discussed. Calibration data obtained through measurements are in good agreement with the results of the FEM analysis. Testing results demonstrate that the sensor features a high sensitivity of 11.098 V/V/Pa in the operating range of 500 Pa at room temperature, and a high-overload resistance (200 times overload) to protect it from being destroyed under atmospheric environment. Owing to the excellent performance, the sensor can be applied for measuring absolute micro pressure lower than 500 Pa. View full abstract»

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  • Nickel–chromium alloy piezoresistive pressure sensor using eutectic bonding

    Page(s): 1184 - 1188
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (305 KB)  

    A nickel-chromium (Ni-Cr) piezoresistive pressure sensor is presented, which has the advantages of low-cost and easy fabrication processes. In the designed sensor, Ni-Cr alloy (80:20-wt-), which can be fabricated using simple processes, is used as the strain-detecting material with a smaller but acceptable gauge factor. Eutectic-bonding technology, based on silver-tin (Ag-Sn) alloy, which contains 3.5-wt- Ag and has 20--m thickness, is used as an alternative and easy bonding choice to complete the vacuum package. Normally, Ag-Sn alloy is mostly obtained by the electrochemical deposition method. However, here the Ag-Sn solder film is directly used as a bonding material. It reduces the fabrication difficulty of eutectic bonding of the proposed pressure sensor. By studying the processes of annealing of Ni-Cr fabrication and eutectic bonding with Ag-Sn, the authors complete the alloy piezoresistive atmosphere pressure sensor. Bonding quality is evaluated by inspection through the deflection of a diaphragm of silicon with more than 95- of the area successfully bonded. The pressure-voltage characteristic test results suggest a precision within 0.3- in square fitting. The temperature coefficient offset is 620-ppm/(-C free space optic (FSO)). View full abstract»

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  • Polymer MEMS pressure sensor arrays for fish-like underwater sensing applications

    Page(s): 1189 - 1192
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Blind cave fish are capable of sensing flows and movements of nearby objects even in dark and murky water conditions with the help of arrays of pressure-gradient sensors present on their bodies called lateral-lines. To emulate this functionality of lateral-lines for autonomous underwater vehicles, an array of polymer MEMS pressure sensors have been developed that can transduce underwater pressure variations generated by moving objects. Individual sensors are fabricated using liquid crystal polymer as a membrane material, which gives high robustness and reliability, and higher sensitivity compared with its silicon counterparts. The individual sensor in the array achieves a sensitivity of 90 mV/(m/s) with a high resolution of 25 mm/s. The underwater object detection capability of the array is demonstrated through proof-of-concept experiments. The array is capable of determining the velocity and distinguishing various distances of an underwater stimulus with high accuracy and repeatability. View full abstract»

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  • Flexible capacitive sensor encapsulating liquids as dielectric with a largely deformable polymer membrane

    Page(s): 1193 - 1196
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    Flexible and highly-sensitive capacitive sensors that are capable of detecting pressure distribution on curved surfaces are now in demand. Using solid dielectric material could limit the sensors flexibility, while using air as the dielectric might compromise the sensors sensitivity. Proposed is a distributed capacitive sensor that contains highly dielectric liquid, which increases the sensor sensitivity while maintaining their flexibility. Since the liquid used in this work is incompressible, an escape reservoir is used that allows the liquid between the electrodes to flow into the reservoir when external pressure is applied and the gap between the electrode decreases. In prior work, the escape reservoir was designed to be alongside the sensing area, which resulted in a large footprint. A sensor has been designed that contains encapsulated highly dielectric liquid and allows the liquid to escape beneath the sensing area. The footprint was successfully reduced by 75%. The encapsulated liquid enhanced the maximum measurable pressure from 100 kPa to 800 kPa. The amplification ratios of the sensitivity with DI water and glycerine increased 7 and 3.5 times respectively, as compared to the device without the liquid encapsulated. View full abstract»

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  • Micro electrochemical sensor with copper nanoclusters for nitrate determination in freshwaters

    Page(s): 1197 - 1201
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (513 KB)  

    A microsensor chip was fabricated by micro electromechanical system technology, and a portable electrochemical system for nitrate determination in freshwaters was developed. As the electrocatalyst material, copper was electrodeposited onto the working-electrode of the microsensor by the cyclic voltammetry method. It was found that the deposited layer was porous and constructed by copper nanoclusters. The electrochemical response of the modified microsensor for nitrate under acidic conditions (pH=2.0) was characterised by linear sweep voltammetry. Calibration in standard nitrate samples in the range of 6.25=300==mol/l yielded straight lines: y1 [μA]μμ0.0526x-3.905 (R12=0.9993), while in the range of 300=3500==mol/l yielded straight lines: y2 [μA]μμ0.0353x-13.653 (R22=0.9918). It was found that the modified microsensor performed at higher sensitivity in nitrate detection than previous works and the limit of detection is 5==mol/l (S/N≥3). Interference analysis with nine kinds of ions (NO2-, Cl-, HPO42-/PO43-, SO42-, HCO3-/CO32-, Na+ and K+) commonly found in water indicated that only NO2- causes reasonable interference (i.e. 10% signal distortion). Based on the modified microsensor, the developed portable electrochemical system was employed for nitrate determination in three freshwater samples. The results were in good agreement with the data obtained by the ultraviolet spectrophotometric method. View full abstract»

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  • Towards optimised wireless Love wave biosensor with high sensitivity

    Page(s): 1202 - 1205
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (255 KB)  

    A Love wave biosensor, which is composed of a one-port surface acoustic wave reflective delay line on a piezoelectric substrate, a thin overlayer (waveguide layer) on top of the substrate, and a sensitive film that responds only to a specific cell, was optimally designed on a 41° YX LiNbO3 substrate and then fabricated according to the extracted design parameters. Based on multilayer theory, polymethylmethacrylate waveguide thickness was optimised. For derivation of the coupling of mode parameters, the periodic using the periodic finite-element method/boundary element method modelling was utilised. Optimal interdigital transducers and reflectors' features were determined to realise high-quality reflection peaks. The experimentally measured reflection coefficient S11 showed good agreement with simulated results. The evaluated sensitivity was 11.5 deg/ g/ml in terms of anti-DNP immunoglobulin G absorption. View full abstract»

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  • Finite element analysis of microneedle insertion into skin

    Page(s): 1206 - 1209
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    A report is presented on the modelling and verification of microneedle-skin interactions. A nonlinear finite element model based on the micro biomechanical properties of skin was established to simulate a microneedle being inserted into the skin. The deformation of skin and the force-displacement behaviour of the microneedle could be obtained. The accuracy was experimentally verified by measuring the relationship between force and displacements during insertion into mouse skin. With this model, the influences of different geometries on microneedle fracture were discussed, which was useful to optimise the microneedle design. View full abstract»

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  • Minimising plasma irradiation area by micronozzle device towards single-cell treatment

    Page(s): 1210 - 1212
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (181 KB)  

    A micro plasma-nozzle device has been fabricated for plasma treatment for a single cell. The micro plasma-nozzle device consists of throughhole and trench structures. The nozzle device was attached to a guide tube (O.D.: φ1.5 mm, I.D.: φ1 mm) of an atmospheric pressure microplasma. Once plasma gas was supplied into the guide tube, most of the plasma gas was exhausted through trench structures, whereas the remaining plasma was excited through the nozzle hole. The nozzle device with φ5 μm holes achieved minimum plasma irradiation onto a PDMS film. The plasma-modihed area was φ.4-5.6 μm, which was much smaller than the area size modified by direct plasma irradiation from the guide tube (φ3-4 mm). The plasma irradiation caused protrusions on the PDMS surface. The minimised plasma irradiation formed 170 nm-height-protrusion-structures on the PDMS surface. The plasma irradiation through the nozzle device was applied to an onion tissue using a nozzle device with φ10 mm holes. The plasma irradiation formed φ-15 μm holes in the onion cell membrane. View full abstract»

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  • Flow-type microbial chip for screening of a single bacterium

    Page(s): 1213 - 1216
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (273 KB)  

    A microbial chip is demonstrated that immobilises microbes into micro holes using positive dielectrophoresis (DEP) for efficient screening. The DEP frequency was set at 10 MHz, which was found to be most effective to selectively immobilise live bacteria. The media including reactive agents can be flown into the chip continuously and therefore the reaction products can be continuously collected. Immobilisation of microbes enables quantification of the number of microbes involved in the reaction and makes their reactions conditions consistent. These advantages enable the proposed microbial chip to evaluate the production capacity of a single bacterium. To demonstrate it, the developed microbial chip was used to characterise microbes and evaluate biological activity. First, Corynebacterium bacterium was used as a sample bacteria. The chip successfully revealed the production capacity of lactic acid by a single C. bacterium. It was experimentally found that the production rate of lactic acid of Corynebacterium glutamicum increased 1.7 times and 3.8 times by adding pyruvic acid and sodium bicarbonate, respectively. Secondly, microbes belonging to the Corynebacterium group with respect to the lactic acid production were screened. Corynebacterium variabile was experimentally found to be the most productive among three tested members. The proposed microbial chip is readily applicable to an efficient microbial screening platform and potentially a reliable microbial sensor given the capacity of quantifying the total number of bacteria involved in the microbial reaction. View full abstract»

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  • Interaction between microspheres of collagen/biphasic calcium phosphate and mesenchymal stem cells

    Page(s): 1217 - 1219
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    Collagen has been widely used as biomaterials for its excellent biocompatibility and the potential to guide tissue regeneration. Based on the inducing regeneration concept, collagen/biphasic calcium phosphate microspheres (BCP) were prepared by utilising emulsion polymerisation and the intrinsic self-assembly of collagen. The bioactivity of the micro collagen/BCP composites was preliminarily evaluated by in vitro co-culture with mesenchymal stem cells (MSCs) and the results indicated that the composites can provide an appropriate environment for the proliferation and osteogenic differentiation of MSCs and have a potential clinical application in the bone tissue engineering field. View full abstract»

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  • Non-planar surface bonding with spray-coated SU-8 as adhesive layer

    Page(s): 1220 - 1222
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (218 KB)  

    In this study, substrates with a large topography were aligned and bonded, and a spray-coated SU-8 was employed as the adhesive layer between two complementary non-planar surfaces. Both wafer-level and chip-level bonding were carried out with an alignment tolerance of 5 m. The bonding pairs exhibited enhanced tensile strength and shearing strength compared to that of the planar surface bonding, which was influenced by the gap between the bonding surfaces. This technology meets the requirements of the wafer-level three-dimensional structure transfer and opens up possibilities for manufacturing more complicated microelectromechanical systems devices. View full abstract»

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  • Micro fabrication of lead-free (K,Na)NbO3 piezoelectric thin films by dry etching

    Page(s): 1223 - 1225
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (242 KB)  

    Micro fabrication has been conducted for sodium potassium niobate [(K,Na)NbO3, KNN] thin films by dry etching and Pt/KNN/Pt unimorph micro cantilevers have been fabricated as a lead-free piezoelectric micro electro mechanical system (MEMS). KNN etching by Ar/C4F8 plasma showed a high etching rate of about 60 nm/min and KNN/Cr selectivity of over 5. Tip displacement of the Pt/KNN/Pt micro cantilevers was measured and the frequency response and piezoelectric properties were evaluated. Young s modulus and piezoelectric coefficients d31 of the KNN thin film were estimated to be 115 GPa and 99 to 219 pm/V, respectively. These results indicate that Ar/C4F8 plasma etching does not degrade the piezoelectric properties of KNN thin films and enables one to fabricate various lead-free piezoelectric MEMS applications. View full abstract»

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  • Characteristic investigation of a static micro polymerase chain reaction chip based on in situ electrochemical detection

    Page(s): 1226 - 1229
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    Aiming to meet the ever-increasing challenge of a low cost, portable and real-time sensitive detection polymerase chain reaction (PCR) system, a novel in situ electrochemical detection static micro PCR (EC-SμPCR) chip is designed and fabricated. The 10μ10μmm EC-SμPCR chip comprises 12 micro reaction chambers, and each 1500μ1000μ60μμm chamber consists of three modules: a micro heater, a micro temperature sensor and a micro three-electrode system (MTES). Heating, cooling and electrochemical cyclic voltammetry (CV) experiments were carried out to investigate the performance characteristics of each module of the chamber in the EC-SμPCR chip. The results showed that the heating rate of the chip was 1.05μCs-1 with only one micro heater, whereas the cooling rate was 1.01°Cs-1 with natural air cooling. It is worth noting that the bare MTES of the chamber directly detected the oxidation of single-stranded DNA (ssDNA, 10-6 M) with the CV method, furthermore, the oxidation peak current of ssDNA can be increased about 40 after a prepolarisation step. All three modules of the chamber in the EC-S PCR chip work efficiently and reliably, which reveals that the entire chip is ready for further analysis trials. View full abstract»

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  • Micro-machined resonant out-of-plane accelerometer with a differential structure fabricated by silicon-on-insulator–MEMS technology

    Page(s): 1230 - 1233
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (303 KB)  

    A new micro-machined resonant accelerometer with a differential structure enabling the detection of out-of-plane acceleration is described. The microaccelerometer consists of two sensitive structures composed of seismic masses, flexural hinges and double-clamped resonant beams. Owing to thickness differences and neutral axis variations among these three components, in response to an out-of-plane acceleration, the movements of the seismic masses lead to stress build up in flexural hinges, further translated as axial forces applied on resonant beams. In this differential design, under acceleration, one resonant beam is under a tensile stress, whereas the other one is under a compressive stress, producing a differential resonant frequency output. The microaccelerometer was fabricated by a silicon-direct-bonding silicon-on-insulator wafer with MEMS fabrication and a low-stress packaging method was also developed. Based on a closed-loop control circuit for resonant beam excitation and detection, device characterisation was conducted, producing a quality factor of 436 in air and a differential sensitivity of 813 Hz/g. View full abstract»

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  • Regulating parameters of electromagnetic micromachined vibrating ring gyroscope by feedback control

    Page(s): 1234 - 1236
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (271 KB)  

    Presented is a method that can regulate the resonant frequency and the quality factor (Q-factor) of an electromagnetic vibrating ring gyroscope by electronic tuning. A novel circuit is designed to control the drive mode of the electromagnetic vibrating ring gyroscope. The circuit consists of an amplifier and a phase shifter used for feedback control. The frequency split can be reduced and the Q-factor can be improved through this method. Experimental results show that the frequency shift of the drive mode can be from -6.41 to 6.38-Hz when the phase of the feedback signal shifts -90- compared with the drive signal. The Q-factor in the air can be improved from 522 to 821 when the phase of the feedback signal is not shifted. The sensitivity tests show the effectiveness of the control circuit. View full abstract»

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  • G-band rectangular waveguide filter fabricated using deep reactive ion etching and bonding processes

    Page(s): 1237 - 1240
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    A G-band microelectromechanical system (MEMS) rectangular waveguide iris filter is designed and fabricated. The effects of the metallised layer and iris thickness, and roughness, on filter main performances are investigated. The prototypes were fabricated using MEMS manufacturing techniques. The key technique problems including deep etching, electroplating and bonding are researched and settled. The measured insertion loss can get to be 1.5-2.0-dB, the central frequency is 174-GHz, the bandwidth is 9.6-GHz, and the isolation out of the bandpass is larger than 15-dB. The test results show that the radio frequency MEMS filter meets practical requirements, which proves that it is a successful example for fabricating such rectangular waveguide devices at one to several hundred gigahertz frequencies using such presented processes. View full abstract»

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  • Highly conformal deposition of copper nanocylinders uniformly electrodeposited in nanoporous alumina template for ordered catalytic applications

    Page(s): 1241 - 1245
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (357 KB)  

    Electrodeposition of copper in cylindrical pores of a nanoporous alumina template is investigated. An electrochemical deposition mode with pulsed current is used in an aqueous copper sulphate solution. The evolution of the deposition quality in terms of height, shape and filling ratio is analysed against several parameters: the intensity, duration and number of pulses. Systematic observations and analyses using scanning electron microscopy are carried out. Statistical and quantitative treatment has been performed. A high filling ratio of more than 90%, the height control and a conformal shape of the copper nanoparticles have been achieved. View full abstract»

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  • Dynamics of carbon nanotubes mass detection involving phonon-tunnelling dissipation

    Page(s): 1246 - 1250
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (334 KB)  

    Nanomechanical (NEMS) resonators made from carbon nanotubes (CNTs) have emerged as ubiquitous devices for use in mass detection. Many oscillation behaviours of CNT mass detection have been theoretically studied by the continuum elastic model, albeit their performance is limited by deleterious effects of mechanical damping. Reported are the support-induced losses in generic mechanical resonators because of the tunnelling of mesoscopic phonons between the CNT and its supports. After formulating the problem, the resulting differential equations are solved analytically using the method of multiple scales, and a closed form solution is obtained. The results reveal that the Young's modulus, density and geometric parameters of the CNT not only influence the resonant frequency shift and the system stiffness, but also affect the system vibration amplitude. Moreover, the effect of the supports material on the oscillation is discussed. Also, the phonon-tunnelling dissipation for dynamics of CNT mass detection is highlighted. View full abstract»

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Aims & Scope

Micro & Nano Letters offers express publication of short research papers presenting research conducted at the forefront of micro- and nanoscale science, engineering and technology, with at least one dimension ranging from a few tens of micrometres to a few nanometres.

Full Aims & Scope

Meet Our Editors

Editors-in-Chief
Professor Gwo-Bin Vincent Lee
National Tsing-Hua University, Taiwan

Professor Peter Dobson
University of Oxford, UK