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Acoustic wave sensors : theory, design, and physico-chemical applications

TL;DR: In this article, the authors present a detailed comparison of typical mass sensitivity of Acoustic Sensors Typical Mass Sensitivities of acoustic Wave Devices Classification of Coating-Analyte Interactions and Approximate Energies Adsorbent Materials and Typical Adsorbates Adsorption Capacities of Organic Vapors on Activated Charcoal Examples of Adsors-Based Acoustic Wave Sensors Sorption Capacity of Natural Rubber for Several Organic Solvents Typical Examples of Polymer-Coated Acoustic wave sensors Examples of Biochemical Acoustic-Wave Sensors Cluster
Abstract: Why Acoustic Sensors Fundamentals of Acoustic Wave Devices Acoustic Wave Sensors and Responses Materials Characterization Chemical and Biological Sensors Practical Aspects of Acoustic-Wave Sensors Subject Index Reduced Index Notation Mechanical Properties of Selected Materials Piezoelectric Stress Constants Properties of Several SAW Substrate Materials Acoustoelectric Properties of Several SAW Substrate Materials Moduli Associated with the Strain Modes Generated by a SAW in an Acoustically Thin Film SAW-Film Coupling Parameter and Phase Angles for SAW Propagation in the X-Direction of ST-Cut Quartz FPW Density Determinations for Low-Viscosity Liquids Gravimetric Sensitivities of Acoustic Sensors Qualitative Comparison of Acoustic Sensors Typical Mass Sensitivities of Acoustic Wave Devices Classification of Coating-Analyte Interactions and Approximate Energies Adsorbent Materials and Typical Adsorbates Adsorption Capacities of Organic Vapors on Activated Charcoal Examples of Adsorption-Based Acoustic Wave Sensors Sorption Capacity of Natural Rubber for Several Organic Solvents Typical Examples of Polymer-Coated Acoustic Wave Sensors Examples of Biochemical Acoustic Wave Sensors Cluster Classification of Coatings for Use in a TSM Sensor Array Center Frequency and Dimensions of Commercial TSM AT-Quartz Resonators IDT Design Parameters for ST-Quartz-Based SAW Sensor Devices"
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Journal ArticleDOI
15 Nov 2001-Nature
TL;DR: This work combines several of these developments to fabricate a smart single-chip chemical microsensor system that incorporates three different transducers (mass-sensitive, capacitive and calorimetric), all of which rely on sensitive polymeric layers to detect airborne volatile organic compounds.
Abstract: Research activity in chemical gas sensing is currently directed towards the search for highly selective (bio)chemical layer materials, and to the design of arrays consisting of different partially selective sensors that permit subsequent pattern recognition and multi-component analysis. Simultaneous use of various transduction platforms has been demonstrated, and the rapid development of integrated-circuit technology has facilitated the fabrication of planar chemical sensors and sensors based on three-dimensional microelectromechanical systems. Complementary metal-oxide silicon processes have previously been used to develop gas sensors based on metal oxides and acoustic-wave-based sensor devices. Here we combine several of these developments to fabricate a smart single-chip chemical microsensor system that incorporates three different transducers (mass-sensitive, capacitive and calorimetric), all of which rely on sensitive polymeric layers to detect airborne volatile organic compounds. Full integration of the microelectronic and micromechanical components on one chip permits control and monitoring of the sensor functions, and enables on-chip signal amplification and conditioning that notably improves the overall sensor performance. The circuitry also includes analog-to-digital converters, and an on-chip interface to transmit the data to off-chip recording units. We expect that our approach will provide a basis for the further development and optimization of gas microsystems.

663 citations

Journal ArticleDOI
TL;DR: In this article, the influence of morphology and crystallographic structure on gas-sensing characteristics of metal oxide conductometric-type sensors have been analyzed, and it was concluded that the structural parameters of metal oxides are important factors for controlling response parameters of resistive type gas sensors.
Abstract: This review paper discusses the influence of morphology and crystallographic structure on gas-sensing characteristics of metal oxide conductometric-type sensors. The effects of parameters such as film thickness, grain size, agglomeration, porosity, faceting, grain network, surface geometry, and film texture on the main analytical characteristics (absolute magnitude and selectivity of sensor response (S), response time (τres), recovery time (τrec), and temporal stability) of the gas sensor have been analyzed. A comparison of standard polycrystalline sensors and sensors based on one-dimension structures was conducted. It was concluded that the structural parameters of metal oxides are important factors for controlling response parameters of resistive type gas sensors. For example, it was shown that the decrease of thickness, grain size and degree of texture is the best way to decrease time constants of metal oxide sensors. However, it was concluded that there is not universal decision for simultaneous optimization all gas-sensing characteristics. We have to search for a compromise between various engineering approaches because adjusting one design feature may improve one performance metric but considerably degrade another.

509 citations

Journal ArticleDOI
TL;DR: A comprehensive review of micromachined piezoelectric transducers can be found in this paper, where the authors present a critical assessment of the future trends and promise of this technology.
Abstract: Over the past two decades, several advances have been made in micromachined sensors and actuators. As the field of microelectromechanical systems (MEMS) has advanced, a clear need for the integration of materials other than silicon and its compounds into micromachined transducers has emerged. Piezoelectric materials are high energy density materials that scale very favorably upon miniaturization and that has led to an ever-growing interest in piezoelectric films for MEMS applications. At this time, piezoelectric aluminum-nitride-based film bulk acoustic resonators (FBAR) have already been successfully commercialized. Future innovations and improvements in inertial sensors for navigation, high-frequency crystal oscillators and filters for wireless applications, microactuators for RF applications, chip-scale chemical analysis systems and countless other applications hinge upon the successful miniaturization of components and integration of piezoelectrics and metals into these systems. In this article, a comprehensive review of micromachined piezoelectric transducer technology will be presented. Piezoelectric materials in bulk and thin film forms will be reviewed and fabrication techniques for the integration of these materials for microsensor applications will be presented. Recent advances in various piezoelectric microsensors will be presented through specific examples. This review will conclude with a critical assessment of the future trends and promise of this technology.

498 citations

Journal ArticleDOI
TL;DR: The importance of this subject in biomaterials surface science is emphasized by reducing the "protein-adsorption problem" to three core questions that require quantitative answer, and several changes to the fundamental biophysical chemistry of protein adsorption are proposed.

460 citations