34 research outputs found
Polymer-BaTiO 3 composites: Dielectric constant and vapor sensing properties in chemocapacitor applications
No full textPolymer coated microfabricated interdigitated electrodes arrays for gas sensing applications
No full textInterDigitated Capacitive (IDC) sensor arrays are fabricated with conventional microelectronics-micromachining technologies on quartz substrates. After fabrication, a polymeric well is patterned around each IDC to precisely define the sensing area and thus deposit coatings of various polymers, by drop casting, in a reproducible and controlled manner. The gas sensing performance of the IDC array is presented for humidity and p-xylene.</jats:p
Proton beam micromachined buried microchannels in negative tone resist materials
No full textIn the present work the Atomki, Debrecen microprobe facility has been used to write long tilted structures by 2 MeV protons. For the formation of the structures, two exposures have been carried out at +20° and -20° using a goniometer stage sample holder. The tilted structures were resolved in the negative tone resist materials SU-8 and ADEPR (an aqueous base developable chemically amplified resist). The length of the microchannels was varied between 100 Î1⁄4m and 1000 Î1⁄4m, the wall thickness was less than 10 Î1⁄4m. By applying the developed methodology it was possible to resolve the desired layout through the whole length of the channel. © 2007 Elsevier B.V. All rights reserved
Hybrid integration of microfabricated chemοcapacitor arrays with miniaturized read-out electronics towards low-power gas sensing module
No full textAbstractA hybrid gas sensing module consisting of an array of 8 polymer coated capacitive sensors and low power read-out electronics is introduced. The chemocapacitor array is fabricated with standard microelectronics/micromachining processes allowing for the realization of planar InterDigitated Electrodes (IDEs). The read-out electronics sub- module consists of an analog multiplexer for the sequential measurement of the sensor array elements, a capacitance to 24-bit converter and a USB to I2C interface. The compact hybrid module has been successfully applied in the detection of sub-100ppm concentrations of p-xylene and toluene. The responses to various humidity levels have been also evaluated
Chemocapacitance response simulation through polymer swelling and capacitor modeling
No full textAbstractA methodology for the prediction of chemocapacitor response due to the sorption of analyte without the need for fabrication of the actual devices is introduced. The methodology is based on experimental measurement of volume fraction due to sorption of the analyte through reflectance measurements and electromagnetic modeling for the InterDigitated Electrode (IDE) capacitor. The volume fraction and the capacitance of the device are coupled through the use of Clausius-Mossotti equation for the calculation of dielectric constant of sorbed polymeric film resulting in the prediction of the capacitance change due to the sorption of the analyte
Performance simulation, realization and evaluation of capacitive sensor arrays for the real time detection of volatile organic compounds
No full textCapacitive-type gas sensors rely on changes in the dielectric properties of the sensing polymeric layer due to absorption of Volatile Organic Compounds (VOCs) or moisture. They are promising devices in terms of ease and low cost of fabrication, reversibility and the wide range of sensing material choice. In the present work, the aim is to explore the fabrication issues of the InterDigitated Electrodes (IDE) through a generic simulation model for the prediction of the capacitance of various IDE structures. Based on the simulation results, an IDE layout was selected for the realization and evaluation of chemcapacitor arrays in the presence of different humidity levels and low concentrations of VOCs with dielectric constant close to those of polymers. The extracted results will be further exploited for the fabrication optimization of an InterDigitated Capacitor (IDC) layout with increased selectivity and sensitivity in specific applications. © 2011 Elsevier B.V. All rights reserved
Back‐scattering and X‐ray‐induced correction factors for AES of thin overlayers: Influence on lateral resolution
No full textMonte‐Carlo simulations of the point‐to‐point resolution in scanning Auger microscopy and x‐ray microanalysis of thin overlayers
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