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In this work, the novel fabrication and characterization of elastomeric piezoelectric nanocomposites are explored. Fabrication methods explored herein utilize ball milled barium titanate powder dispersions, along with double walled carbon nanotubes which are dispersed in toluene though the use of an ultrasonic probe. Test devices are then constructed with electrodes made from evaporated gold on polyimide foils and protective dielectrics of pristine PDMS. Two different device construction methods are explored utilizing both direct contact bonding and plasma bonding of the active composite layers to the dielectric/electrode. Test samples are evaluated through the use of a dedicated Berlincourt type piezoelectric d33 meter. © Published under licence by IOP Publishing Ltd.

In this communication, we present the fabrication and the characterisation of micro-heating elements made on polyimide (PI) sheets and on spin coated polyimide membranes. Different types of polyimide and heater materials were investigated to realise micro-hotplates for gas-sensing and thermal actuating applications. The effects of the type of polyimide used and of the different annealing performed on the mechanical and electrical properties of the metallic heaters were characterised. Using an optimised combination of materials and processes, flexible micro-hotplates on polyimide sheets and on polyimide membranes on silicon were realised and their thermal properties evaluated. Platinum and aluminium micro-heating elements on polyimide exhibited promising characteristics for their integration in low-power gas sensors and thermal actuators.

Vertical comb drive actuators are now frequently used for rotating micromirrors. For constructing the vertical comb, paired combs positioned at different heights are necessary. In many cases, Si dry etching is carried out from front and bottom surfaces of SOI wafer. The alignment accuracy between combs depends on the aligner accuracy. The backside Si etching becomes very deep with the increase of technical difficulty. In this study, a new method for realizing the vertical comb in SOI-MEMS and its performance is examined.

This paper reports on the downscaling of solid propellant pyrotechnical microsystems. Sub-millimeter scale micro-thrusters were fabricated in silicon to investigate the limit of integration of this technology. The dimensions of the micro-thrusters chamber and of the igniter were reduced and a highly energetic solid-state propellant was used, the ZPP. Deep reactive ion etching (DRIE) of silicon was used to fabricate the chamber surrounded by thermal insulating grooves. The diverging part of the nozzle was also etched by DRIE, with a maximum angle of 3/spl deg/, and integrated to the igniter part. The igniter was made up of surface micromachined polysilicon micro-heaters, consisting in 2 to 16 parallel heating bridges. An electrical power of 200 mW per beam could be delivered for a few seconds. A minimum temperature of 450/spl deg/C has been reached with 130 mW per beam. Successful ignition of the propellant shows the capability of this promising technology to integrate arrays of devices within a limited area of silicon.

In this communication, we report on metal to glass anodic bonding for Microsystems packaging. Bonded Pyrex-Foturan/Metal double stack and Silicon/Pyrex/Metal triple stack were investigated for applications in the sensor encapsulation field. Anodic bonding of metals, sheets of Invar, Kovar, Alloy 42 and Titanium, and thin films of Titanium, to Ion-containing glasses with two different thermal expansion coefficients, Pyrex and Foturan, was evaluated in terms of samples preparation, bonding parameters, and bonding characteristics. Selected metals anodically bonded to glass exhibited levels of residual stress, strength and tightness that make this technique suitable for packaging Microsystems, silicon piezoresistive sensors and micro-fluidic systems, among others.

We report on the reliability of micro-hotplates used in gas sensing applications. Accelerated ageing of the micro-hotplates was obtained using a burn-in test. Devices with different designs were self-heated at higher temperatures than their typical operating temperature until failure. Results on micro-hotplates with only the heater, the heater and electrodes, and coated with the gas-sensitive coating are presented. Electromigration and breaking of the membrane were two failure modes observed, and for some testing conditions were linked together. The electrodes had a slight effect on the maximum power before failure and on the membrane deformation, but had an influence on the micro-hotplates lifetime. The addition of the gas-sensitive coating provided a longer lifetime.

The influence of high temperature post-processes on the microstructural, electrical, and mechanical properties of evaporated platinum thin films with tantalum as adhesion layer was investigated. Post-processes, such as deposition of a silicon nitride passivation layer by LPCVD and annealing at high temperature (up to 830°C) in an inert or reactive gaseous atmosphere, were performed separately or successively on platinum/tantalum films having different thickness. An abnormal grain growth and a grain reorientation occurred in the platinum films during the heat treatments, with more severe hillocks formation when performed in air at temperatures higher than 500°C. Another parameter influencing the electrical characteristics (resistivity, temperature coefficient of resistance) of these films, in addition to the post-processing temperature and time, was the thickness of the platinum film.A passivation made of LPCVD silicon nitride film was shown to stabilise the electrical properties of the Pt/Ta films before post-processing or operating them at high temperatures, up to the deposition temperature of the passivation film. However, if the passivation is removed, postprocessing of the Pt films at a higher temperature than 500°C in air induced more or less severe hillocks formation and adhesion problems could occur, related to the oxidation of tantalum. The adhesion of the Pt/Ta films was found to depend on the thickness of the LPCVD silicon nitride film deposited, which was removed before annealing in air. The Pt/Ta films properties depend on the annealing conditions, time and temperature, and on the history of the film, if the annealing was performed just after its deposition or after successive thermal processes.

The design optimization through modeling of a thinned bulk-PZT-based vibration energy harvester on a flexible polymeric substrate is presented. We also propose a simple foil-level fabrication process for their realization, by thinning the PZT down to 50 mu m and laminating it via dry film photoresist onto a PET substrate at low temperature (

This paper presents experimentally-verified multiphysics finite element model of a wideband vibration energy harvester with impact coupling, which operates on the principle of frequency up-conversion: under low-frequency harmonic base excitation a cantilever-type resonator (with resonant frequency of 18.8 Hz) impacts a high-frequency piezoelectric cantilever, which starts freely vibrate at its resonant frequency of 374 Hz. Such input frequency amplification enables efficient power generation under low-frequency ambient excitations. The model was implemented in COMSOL and the contact between the cantilevers was formulated by using a nonlinear viscoelastic model. Reported results of dynamical and electrical testing of the fabricated vibration energy harvester confirm the accuracy of the model as well as reveal some operational characteristics of the device under varying impact and excitation conditions.

This paper presents the fabrication and characterization of multilayer PVDF resonant micro-vibrational energy harvesters designed to withstand environments in which high levels of acceleration are present. The multilayer cantilevers are fabricated by combining two folded PVDF stacks into a multilayered, bimorph structure. This acts to increase the overall capacitance of the harvester, a problem that plaques PVDF cantilevers as a result of its low dielectric constant. Moderate powers (7 mu W) are produced from the cantilevers even at high acceleration levels (20 g) due to the limited piezoelectric coefficient of PVDF; however, as a result of the high tensile strength and low elastic modulus of PVDF, the cantilevers are able to survive extremely high accelerations (> 4000 g) without breakage - a critical problem for harvesters based on brittle piezoelectric materials and substrates.

Interdigitated electrodes are common structures in the fields of microelectronics and MEMS. Recent developments in flexible electronics compel an understanding of such structures under bending constraints. In this work, the behavior of interdigitated micro-electrodes when subjected to circular bending has been theoretically and experimentally studied through changes in capacitance. An analytical model has been developed to calculate the expected variation in capacitance of such structures while undergoing outward and inward bending along the direction perpendicular to the electrodes. The model combines conformal mapping techniques to account for the electric field redistribution and fundamental aspects of solid mechanics in order to define the geometrical deformation of the electrodes while bending. To experimentally verify our theoretical predictions, several interdigitated electrode structures with different geometries were fabricated on polymeric substrates by means of photolithography. The samples, placed in a customized bending setup, were bent to controlled radii of curvature while measuring their capacitance. A maximum variation in capacitance of less than 3% was observed at a minimum radius of curvature of 2.5mm for all the devices tested with very thin electrodes whereas changes of up to 7% were found on stiffer, plated electrodes. Larger or smaller variations would be possible, in theory, by adjusting the geometry of the device. This work establishes a useful predictive tool for the design and evaluation of truly flexible/bendable electronics consisting of interdigitated structures, allowing one to tune the bending influence on the capacitance value through geometrical design. (c) 2013 AIP Publishing LLC.

This work presents the simultaneous fabrication of ambient relative humidity (RH) and temperature sensors arrays, inkjet-printed on flexible substrates and subsequently encapsulated at foil level. These sensors are based on planar interdigitated capacitors with an inkjet-printed sensing layer and meander-shaped resistors. Their combination allows the compensation of the RH signals variations at different temperatures. The whole fabrication of the system is carried out at foil level and involves the utilization of additive methods such as inkjet-printing and electrodeposition. Electrodeposition of the printed lines resulted in an improvement of the thermoresistors. The sensors have been characterized and their performances analyzed. The encapsulation layer does not modify the performances of the sensors in terms of sensitivity or response time. This work demonstrates the potential of inkjet-printing in the large-area fabrication of light-weight and cost-efficient gas sensors on flexible substrates.

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Free-standing yttria-stabilised-zirconia (YSZ) thin films can be found in today's miniaturised gas sensors and as electrolytes in micro-solid oxide fuel cell membranes. 8 mol.% YSZ thin films prepared by pulsed laser deposition on silicon substrates are investigated by wafer curvature and nanoindentation. The 300nm thin 8YSZ films deposited at 700°C have a compressive stress of -1100±150 MPa and a Young's modulus of 205±20 GPa at 25 °C. The corresponding free-standing 8YSZ membranes are investigated by light microscopy and white light interferometry. The 8YSZ membranes deposited at 700°C have a buckling shape with a C4z-rotational symmetry and buckling amplitude of 6.5μm at 25°C. Numerical simulations of the buckling patterns using the Rayleigh-Ritz-method are in good agreement with the experimental data. These simulated buckling patterns are used to extract the local stress distribution. This is important regarding the application of YSZ membranes in micro-solid oxide fuel cells which must be thermomechanically-stable during device operation.

This paper presents a new fabrication method to manufacture alkali reference cells having dimensions larger than standard micromachined cells and smaller than glass-blown ones, for use in compact atomic devices such as vapour-cell atomic clocks or magnetometers. The technology is based on anodic bonding of silicon and relatively thick glass wafers and fills a gap in cell sizes and technologies available up to now: on one side, microfabrication technologies with typical dimensions

Reference EPFL-ARTICLE-171328doi:10.1016/j.snb.2011.04.030View record in Web of Science Record created on 2011-12-16, modified on 2016-08-09

Reference EPFL-ARTICLE-172287doi:10.1016/S0924-4247(10)00361-4View record in Web of Science Record created on 2011-12-16, modified on 2017-05-10

In this paper, we introduce a charge integrator as a read-out system for piezoelectric cantilever sensors. The charge integrator is used to monitor the surface charge induced by piezoelectric materials as a function of mechanical stress. This technique improves the response of piezoelectric cantilever sensors in low-frequency measurements, which makes them suitable for chemical and biological detection. Furthermore, it is capable of real-time, portable and all-electrical detection. The detection of alkanethiols on the Au-coated piezoelectric cantilevers is demonstrated to verify the concept.

A generic method for the packaging of transducers at the foil level is proposed and was demonstrated on chemical gas sensors made on a plastic foil. The processing was based on the lamination of pre-patterned polymeric structures on the fabricated devices and covered by a gas permeable membrane. This polymeric packaging can be either applied on plastic foils or on conventional substrates such as silicon or glass. It can be used when standard packaging techniques might not be applied or when they can represent a significant cost. Using the lamination of a foil, the dry process presented here is compatible with large-scale fabrication techniques, such as roll-to-roll processing, and aims at reducing the global fabrication cost of sensing devices made on a plastic foil. It can further lead to the fabrication of all polymeric devices. This generic processing can be used for a wide range of applications in the field of microsystems, especially for which the foil level is required and where standard techniques at the wafer level are not applicable. The foil level packaging (FLP) was implemented here for the encapsulation of gas sensors on a plastic foil and validated through gas measurements.

International audience; We report on the dynamic and static thermal characterization of microsystems using a visible and near-infrared (NIR) thermography system based on a low-cost standard CCD sensor. The interest of this method is that it is possible to obtain a true spatial resolution better than 500 nm, which is necessary in high spatial resolution applications (microsystem applications). Another interesting point of this optical method is that the temperature error versus the emissivity error is always very low (compared to infrared thermography). We show, in this study, that this behavior originates in the high sensitivity of Planck's law in this wavelength range (compared to infrared range). Thus, we demonstrate the principal advantages of this method for micromachined heater application. Thermal measurements (in dynamic and static modes) were performed on micro-heaters commonly used in microsystems, platinum- and silicon-based micromachined heaters. The results show the capability of the method in terms of the thermal resolution and spatial resolution as well as the capacity to quickly obtain static and dynamic thermal images of the studied sample.

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The hydrogen response of gas-sensitive field-effect devices is mainly due to trapping of atomic hydrogen on the insulator side of the metal-insulator interface of the metal-insulator-semiconductor (MIS) structure. Therefore an influence of the choice of insulator on the hydrogen response properties is expected. We have investigated this influence by producing MIS capacitors with four different insulators; Si O2, Al2 O3, Si3 N4, and Ta2 O5. The results show that the choice of insulator influences the detection limit, the saturation concentration, and the saturation response. Furthermore, there is a strong correlation between the observed saturation response and the oxygen concentration of the insulator surface, as measured by Auger electron spectroscopy, which indicates that the trapping of hydrogen at the interface occurs at the oxygen atoms of the insulator surface. Finally, if the metal film is porous a catalytic oxidation of the insulator surface appears to be facilitated, which can increase the hydrogen response. © 2005 American Institute of Physics.

This work presents an approach for increasing operational bandwidth of a vibration energy harvester in low-frequency environments by effectively exploiting contact-based frequency up-conversion. It was implemented by a couple of low-frequency resonators with appropriately spaced natural frequencies impacting high-frequency piezoelectric generators when the device is harmonically excited in 10-40 Hz range. A proof of concept was designed, modeled, fabricated and characterized, demonstrating improved power and bandwidth performance (up to 37 μW and 9 Hz at 1g) with respect to traditional single-resonator designs. © 2014 The Authors. Published by Elsevier Ltd.

This communication presents an overview on our activities on the development of printed sensors on flexible polymeric foil for RFID. We are envisioning the direct printing of sensors on different types of products such as smart labels and RFID tags. This technology could bring sensors where there is no sensor at the moment by significantly reducing their production cost and by adding new functionalities. The integration of these sensors fabricated on plastic foil with electronics, communication and powering capabilities will be addressed. The realization of cost-effective smart objects can be one of the key enabling technologies for the deployment of the Internet of Things (IoT).

We present a novel approach to combine wafer level packaging (WLP) with micro-machined hotplate gas-sensing elements (Patent Application WO03067241 2003-08-14). This concept allows liquid tight sealing of gas sensor devices, protecting them during production (e.g. wafer dicing) and later in the application, while still allowing the target gases to reach the sensing layer. The basis of the WLP is the combination of a structured Pyrex wafer with a micro-machined substrate wafer. Thereafter, thick film SnO/sub 2/ layers are deposited and stabilized before a diffusion membrane is attached, sealing the wafer stack.

We report on patterning of miniaturized gold (Au) based micro-hotplates reaching high temperature at lower power consumption than ever reported using aerosol jet printing. Efficient heating (i.e. ~12 °C/mW) was achieved by reducing the effective heating area and the thickness of the polyimide substrate. Au nanoparticles solution was used for printing heaters of two different sizes, i.e. 500 × 500 μm2 and 150 × 150 μm2. These double meander heaters were patterned on a 50 μm-thick polyimide substrate implementing 5 μm-thick membranes using laser etching. Finite element simulations were used to optimize the thermal design of the devices. They exhibit a power consumption at 250 °C of 39 mW and 22 mW for the larger and smaller heater design, respectively. These results indorse the significance of aerosol jet printing process at high resolution to realize high temperature and power efficient micro-hotplates on foil for applications such as; in portable gas and chemical sensors, thermal metrology and mapping, localized heating, thermal actuators and microfluidics etc.

We demonstrate a woven textile with an integrated humidity and temperature sensor on flexible PI substrates. We discuss the fabrication process of the smart textile and compare two methods of sensor fabrication, first conventional photo lithography and second printing using ink jet. The humidity sensor is based on a capacitive interdigitated transducer covered with a sensing layer while the temperature sensor is made of a resistive metallic meander. An encapsulation method protecting the sensors during dicing, weaving and operation has been successfully implemented. The fabricated structures are tested to bending strain, a main source of failure during the fabrication of textiles. We were able to bend bare electrodes and complete sensors down to a minimal bending radius of 100 μm without loss of functionality. The woven temperature sensor has a temperature coefficient of 0.0027 /°C for lithography made and 0.0029 /°C for printed sensors. The humidity sensor shows a repeatable behaviour in the tested humidity range between 20 to 70 %RH. The weaving process does not damage or change the behaviour of the fabricated sensors. This contribution will highlight the challenges and promises of printing and laminating processes for the large scale fabrication of smart polymeric stripes to be woven into textiles.

A 4H-SiC pressure sensor with piezoresistive transducers, for harsh environment applications, e.g., high temperature (∼650°C) and/or in corrosive chemicals is presented. The sensing membrane, 1 mm in diameter and 50 µm in thickness, was formed by milling (drilling) a bulk single crystal SiC wafer. Both transverse and longitudinal piezoresistors were formed on the membrane out of an n-type SiC epitaxial layer. Ohmic contacts were obtained with Ta/Ni/Pt metallization followed by annealing at 1000°C for 20 min. The sensor was assembled on a small board and characterized under hydrostatic pressures up to 60 bar at room temperature. The obtained pressure sensitivity was 268 µV/V/bar. The sensor chip was exposed in air at 600°C for 165 hours and changes in bridge resistance were measured.

This paper reports on the microfabrication and characterization of piezoelectric MEMS structures based on epitaxial Pb(Zr0.2Ti0.8)O-3 (PZT) thin films grown on silicon wafers. Membranes and cantilevers are realized using a sequence of microfabrication processes optimized for epitaxial oxide layers. Different issues related to the choice of materials and to the influence of the fabrication processes on the properties of the piezoelectric films are addressed. These epitaxial PZT transducers can generate relatively large deflections at low bias voltages in the static mode. Estimations of the piezoelectric coefficient d(31) of the epitaxial PZT thin film (100 nm) yield 130 pm V-1. In the dynamic mode, the performance of the epitaxial PZT transducers in terms of the resonant frequency, modal shape and quality factor are examined. An epitaxial PZT/Si cantilever (1000 x 2500 x 40 mu m(3)) resonating in air and in vacuum exhibits a deflection of several microns with quality factors of 169 and 284, respectively. For a 1500 mu m diameter membrane, the quality factor is 50 at atmospheric pressure, and this rises to 323 at a pressure of 0.1 mbar. These results indicate the high potential of epitaxial piezoelectric MEMS, which can impact a variety of technological applications.

This paper presents the development of a gas pre-concentrator based on a micro-reactor in porous silicon filled with carbon nanopowders in solution. The particularity of this microsystem is its applicability in the fields of atmospheric pollution monitoring and explosives detection. The performances of the device are closely related to the design of the micro-reactor and the choice of the adsorbent material. The benefits of using porous silicon to ease the fixing of the carbon absorbent in the reactor and to enhance gas adsorption are also investigated. Preliminary results on a device based on a carbon adsorbent powder filled in a porous silicon micro-reactor for benzene pre-concentration are reported.

The design, modeling, fabrication, and characterization of solid propellant microthrusters for space application is presented. The operational concept of solid propellant thruster is simply based on the combustion of a solid energetic material stored in a micromachined chamber. Each thruster contains four main parts (nozzle, heater, chamber, seal). Thrusters presented in this paper have a chamber area of 2.25mm2. Throat diameters (160, 250, and 500 μm) have been calculated to generate thrusts in the range from 0.3 to 30 mN that meets station keeping requirements for micro satellites. Fabrication processes for each part of the thruster are presented as well as the assembling procedure and the electronic module implementation. Characterizations give ignition power between 80 and 150 mW depending on the energetic material contained in the igniter's cavity. The ignition success is of 100% when using a Zirconium Potassium Perchlorate propellant. Thrust balance is presented as well as the thrust measurements that validate our model. © 2006 IEEE.

The physical and electrical characterizations and modeling of several patterns printed by ink-jet and screen printing are presented in this work. The main goal was to determine suitable techniques to manufacture RFID antennas by using different conductive Ag inks, pastes and substrates commonly used in RFID. The physical characterization consisted of measurements of the layer thickness and Root Mean Square roughness of the patterns. An analytical model has been used to predict the thickness of the ink-jet printed pattern based on the printing conditions and the chemical composition of the conductive ink. DC electrical characterization has been carried out to study different conductive inks and substrates, and the lowest sheet resistance has been identified four every analyzed case. Finally, inductors have been fabricated by ink-jet printing using the optimal conditions obtained from this work, Sun Tronic U5603 Ag ink and Polyetherimide substrate to validate the present study.

This paper reports on the design of a microsystem-based thermal gas viscometer used for the determination of the quality of natural gas and its optimization through modification of its two main components: the hotplate and the capillary tube. Features, such as ultra-low power consumption (95%), robustness, and cost-effective mass production are the key outcome from this optimization. Two different technologies were investigated for the integrated hotplate: thick film technology using screen printing on a ceramic substrate and silicon technology based on thin films’ deposition and silicon micromachining. The sensors have been evaluated both numerically and experimentally for gas mixtures composed of nitrogen, methane, and ethane. The sensor with silicon hotplate exhibited superior performances in terms of power consumption, thermal time constant, and reproducibility of manufacturing process. The impact of the geometry of the hotplate on the performance of the sensor was investigated and the optimum design identified. The electro-thermo-mechanical tests confirmed its long-term stability. Finally, the reduction of the response time of the sensor was evaluated by modifying the diameter of its capillary tube. The experimental results showed that by increasing the diameter of capillary tube from 20 to $30~\mu \text{m}$ , the response time of the sensor decreased from 60 to 25 s.

Local thermal probing has become a major tool for studying transport phenomena at micro and nanoscale levels, detecting hot spots and failures of microelectronic devices or measuring surface temperature distribution at these scales. If contact point measurement of a local tip is expected to provide the best spatial resolution, the fundamental aspect of the interaction between the probe tip and the sample remains the key point on which any quantitative measurement relies. We focus on the calibration procedure that will allow measuring the thermal response (error) of a contact probe used for temperature measurement on a surface. For this purpose, a micro-hotplate made of platinum heater suspended on thin silicon nitride (SiN) membrane represents an interesting tool. The objective is to develop heated reference samples with localized temperature sensors embedded on its surface to probe the temperature during the probe contact. We report on the thermal design of low-power calibration chip and the first results obtained when contacting wire based micro-Thermocouple Scanning Thermal Microscope (SThM) probes. © 2015 IEEE.

This work reports on thermally isolated electronic components for gas sensing applications. The device is composed of an array of 4 MOSFETs, a diode and a semiconductor resistor integrated on a micro-hotplate, which is fabricated using bulk micromachining of silicon. The thermal efficiency of the device is 2/spl deg/C/mW with a thermal constant less than 100 ms. Holes are made in the passivation film over the gates of the MOSFET and gas sensitive films deposited on top of the gate insulator. The low thermal mass device realized allows new modes of operation for MOSFET gas sensors such as a combination of the field and thermal effects and a pulsed temperature mode of operation.

The evaluation of colorimetric films for the detection of low concentrations of gaseous ammonia in a waveguide configuration is presented. They were composed of a pH indicator selective to NH3 embedded in a polymeric matrix and deposited on an optical waveguide to improve the sensitivity. Since the film aims at being integrated onto flexible plastic foil, a plasticizer was added to allow bending of the film without cracking. The different components were dissolved in a proper amount of solvents to obtain spin-coatable sub-µm thin films. They were successfully deposited onto glass waveguides to evaluate their optical properties and gas sensing abilities. The influences of the matrix composition and the pH indicator used on their gas sensing characteristics are presented. All films exhi bited a very good selectivity and cross-selectivity towards NH3. A matrix composed of bromophenol blue and PMMA exhibited the best sensing properties. The adequate choice of plasticizer has shown a significant reduction on the sensitivity of the film to humidity at the cost of a slower kinetics of reaction. Concentrations as low as 0.25 ppm of NH3 were easily measured and the theoretical limit of detection of our sensing device was evaluated to be of 2 ppb.

We are reporting energy scavenging from fluid flows inside tubular structures using triboelectric effects. Two separate designs of triboelectric generators are proposed. A tubular design that uses liquid-solid interaction mechanism for water, and freestanding flapping films design utilizing contact-separation mechanism for wind flow energies conversions. The developed generators exhibit capabilities to produces power from fluid motions through the tube. Osmotic water having conductivity of 2.05±0.05 μS/cm provides higher triboelectric responses in comparison to tap water (conductivity of 322.0±2.0 μS/cm) flow. An average power of 37.4 μW for an osmotic water flow of82.5±0.5 cm3/s was generated for two pairs of triboelectric generators. Under a wind flow of 8.2±0.1 m/s and using three pairs of generators an average power of 144.8 μW was obtained across an optimum load resistance (RL ) of 7.6 MΩ.

We report on printed strain sensors on several meters long PET fibers for integration in textile at large scale. The sensors are made by locally inkjet printing capacitive transducers on cylindrical PET fibers used in industrial textiles. Sensor measurements were performed for strains up to 1%. 10 meters long functionalized PET fibers were woven with metallic interconnect fibers using large scale industrial weaving machine and resulted in a 1 m2 smart textile demonstrator. Applications are foreseen in predictive maintenance of industrial textiles and in the automotive industry. © 2015 The Authors. Published by Elsevier Ltd.

Platinum/tantalum/silicon ohmic contacts were designed, fabricated and characterized to withstand high-temperature post-processing: the ohmic behavior was maintained after 1 h annealing, at temperatures up to 850 degrees C in an oxidizing environment. A LPCVD silicon nitride layer was added to passivate the contacts from oxidation and concentrated wet hydrofluoric acid (HF 49%) process steps; the later being widely used for the release of free-standing MEMS structures. The linear Transfer Length Method (TLM) was implemented to infer the specific contact resistance at the metal-silicon interface. The Pt/Ta/Si contacts were studied as part of the fabrication process of high-temperature Through Silicon Vias (TSVs). The fabricated KOH-TSVs are dedicated to a "via first" 3D-integration of a delicate RF-MEMS device. They are also of interest for harsh-environment silicon-based MEMS applications: one-week operation test at high-temperature, up to 450 degrees C, showed a high electrical resistance stability. (C) 2012 Elsevier B.V. All rights reserved.

Fully casted wearable soft triboelectric devices for energy harvesting and motion sensing are presented. Developed devices feature simple designs and are made of elastomeric materials where scalable fabrication methods can be applied. Film casting and stencil printing techniques were used to deposit polydimethylsiloxane (PDMS), polyurethane (PU) and carbon-based elastomeric materials. The soft triboelectric generator (TENG) with sliding design provides a higher output density of 3.6 μW/cm2 in comparison to 0.05 μW/cm2 for the vertical mode design, at operational frequency of 0.9±0.2 Hz. These soft TENGs demonstrated sensing and energy scavenging capabilities from body movements.

In this paper, we investigate the performance of a piezoelectric membrane actuated by an epitaxial piezoelectric Pb(Zr0.2Ti0.8)O-3 (PZT) thin film for localized-mass sensing applications. The fabrication and characterization of piezoelectric circular membranes based on epitaxial thin films prepared on a silicon wafer are presented. The dynamic behavior and mass sensing performance of the proposed structure are experimentally investigated and compared to numerical analyses. A 1500 mu m diameter silicon membrane actuated by a 150 nm thick epitaxial PZT film exhibits a strong harmonic oscillation response with a high quality factor of 110-144 depending on the resonant mode at atmospheric pressure. Different aspects related to the effect of the mass position and of the resonant mode on the mass sensitivity as well as the minimum detectable mass are evaluated. The operation of the epitaxial PZT membrane as a mass sensor is determined by loading polystyrene microspheres. The mass sensitivity is a function of the mass position, which is the highest at the antinodal points. The epitaxial PZT membrane exhibits a mass sensitivity in the order of 10(-12) g/Hz with a minimum detectable mass of 5 ng. The results reveal that the mass sensor realized with the epitaxial PZT thin film, which is capable of generating a high actuating force, is a promising candidate for the development of high performance mass sensors. Such devices can be applied for various biological and chemical sensing applications. (C) 2010 Elsevier B.V. All rights reserved

We report a novel biodegradable piezoelectric composite fabricated from paper and the piezoelectric salt, sodium potassium tartrate tetrahydrate (Rochelle salt, which we term PiezoSalt). The piezoelectric composite is non-toxic and is fabricated free of environmentally harmful solvents by impregnating PiezoSalt into a paper matrix through the crystallization of a concentrated PiezoSalt brine solution. The composite exhibits an effective piezoelectric constant between 3 and 25 pC N-1, dielectric constant of 7, mass density of 625 kg m(-3), and a Young's modulus between 7 and 8 GPa. When directly actuated, cm-scale cantilevers consisting of PiezoSalt paper produced clearly audible sound waves, illustrating one potential application. PiezoSalt paper composite provides a scalable, high throughput approach for biodegradable sensors and transducers with unsurpassed environmentally friendly processing. (C) 2016 Elsevier B.V. All rights reserved.