Recent Submissions

Now showing 1 - 5 of 27
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    High-Conductivity Stoichiometric Titanium Nitride for Bioelectronics
    (Wiley-VCH GmbH, 2023-02-02) Gablech, Imrich; Migliaccio, Ludovico; Brodský, Jan; Havlíček, Marek; Podešva, Pavel; Hrdý, Radim; Ehlich, Jiří; Gryszel, Maciej; Glowacki, Eric Daniel
    Bioelectronic devices such as neural stimulation and recording devices require stable low-impedance electrode interfaces. Various forms of nitridated titanium are used in biointerface applications due to robustness and biological inertness. In this work, stoichiometric TiN thin films are fabricated using a dual Kaufman ion-beam source setup, without the necessity of substrate heating. These layers are remarkable compared to established forms of TiN due to high degree of crystallinity and excellent electrical conductivity. How this fabrication method can be extended to produce structured AlN, to yield robust AlN/TiN bilayer micropyramids, is described. These electrodes compare favorably to commercial TiN microelectrodes in the performance metrics important for bioelectronics interfaces: higher conductivity (by an order of magnitude), lower electrochemical impedance, and higher capacitive charge injection with lower faradaicity. These results demonstrate that the Kaufman ion-beam sputtering method can produce competitive nitride ceramics for bioelectronics applications at low deposition temperatures.
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    Circuits for the Charge Push-through Electronics: Power Efficient Signal Processing Inside the Artificial Cochlear Implant
    (Elsevier, 2016-09-04) Žák, Jaromír; Hubálek, Jaromír; Prášek, Jan; Pekárek, Jan; Svatoš, Vojtěch; Hadaš, Zdeněk; Dušek, Daniel
    This work deals with the new technique called Charge Push-Through technology which is more energy efficient than the currently used approaches. The new energy efficient design regarding utilization of emerging technology such as Energy harvesting (EH) power sources is very promising for future development of energy independent (zero-power) and nonobtrusive cochlear implant. This work presents the solution of Charge Push-Through circuits using the component level design of artificial cochlea.
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    Investigation of ammonia gas sensing properties of graphite oxide
    (Elsevier, 2016-09-04) Bannov, Alexander G.; Prášek, Jan; Jašek, Ondřej; Shibaev, Alexander A.; Zajíčková, Lenka
    In this paper a graphite oxide is investigated as a possible sensing layer of room temperature ammonia chemiresistive gas sensor. The sensing properties were tested in a wide range of ammonia concentrations in air (10-1000 ppm) and under different humidity levels (3-65 %). It was concluded that the graphite oxide based sensor possessed high response to NH3 in synthetic air (R/R0 ranged from 2.5 to 7.4 % for concentrations of 100-500 ppm and 3 % relative humidity) with negligible cross-sensitivity towards H2 and CH4. It was determined that the sensor recovery rate was improved with ammonia concentration growth. Increasing of ambient relative humidity led to increase of sensor response. The highest response of 22.2 % for 100 ppm of ammonia was achieved at 65 % relative humidity level.
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    A Self-Compensating System for Fixed Pattern Noise Reduction of Focal Plane Arrays of Infrared Bolometer Detectors
    (Elsevier, 2016-09-04) Neužil, Pavel; Pekárek, Jan; Svatoš, Vojtěch; Prokop, Roman; Gablech, Imrich; Pavlík, Michal; Fujcik, Lukáš; Hubálek, Jaromír
    This paper describes a self-compensating system for fixed pattern noise reduction (FPNR) of focal plane arrays (FPA) of infrared (IR) bolometer detectors. The proposed system used a modulator of first order which operates as non-saturating current integrator. The method also suppressed the self-heating effect as well as the effect of resistance non-uniformity across the FPA. The read-out circuit (ROIC) was designed in ONSemi I2T100 technology considering the matching and noise effects and fabricated using EUROPRACTICE service. Its verification was made on the test printed circuit board (PCB) with the variable resistors. These resistors were changed to emulate the real bolometer behavior due to IR radiation.
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    AACVD Synthesis and Characterization of Iron and Copper Oxides Modified ZnO Structured Films
    (MDPI, 2020-03-05) Claros Vargas, Martha Carmiňa; Šetka, Milena; Yecid P., Jimenez; Vallejos Vargas, Stella
    Non-modified (ZnO) and modified (Fe2O3@ZnO and CuO@ZnO) structured films are deposited via aerosol assisted chemical vapor deposition. The sulics of these structured films. Static water contact angle measurements for these structured films indicate hydrophobic behavior with the modified structures showing higher contact angles compared to the non-modified films. Overall, results show that the modification of ZnO with iron or copper oxides enhances the hydrophobic behavior of the surface, increasing the contact angle of the water drops at the non-modified ZnO structures from 122 degrees to 135 degrees and 145 degrees for Fe2O3@ZnO and CuO@ZnO, respectively. This is attributed to the different surface properties of the films including the morphology and chemical composition.