Browsing by Author "Kuo, Li-Min"

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A Flexible pH-Sensing Structure Using WO3/IrO2 Junction with Al2O3 Encapsulation Layer
(2013)
Kuo, Li-Min
;
Chen, Kuan-Neng
;
Chuang, Yi-Lin
;
Chao, Shuchi
;
電子物理學系
A diode-like current-voltage characteristic in response to hydrogen-ions based on a WO3/IrO2 diode coated with a membrane-like Al2O3 is reported. Microsensors fabricated with the oxides (IrO2 and WO3) will suffer from interference errors in pH-measurements due to their strong responses to environmental redox species. With ionic-conductive and insulation properties, the membrane can mediate the transport of released protons and block the electrons from redox species in solutions. Invoking proton-electron double injection, H+ and e(-) produce redox reactions, which control the conductivity and preserve the continuity of currents across the interface with a good sensitivity (0.168 mu A/pH) between pH = 2 to 12. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.004303ssl] All rights reserved.
A precise pH microsensor using RF-sputtering IrO2 and Ta2O5 films on Pt-electrode
(2014-03-01)
Kuo, Li-Min
;
Chou, Yi-Chia
;
Chen, Kuan-Neng
;
Lu, Chien-Chia
;
Chao, Shuchi
In this study, an easily implemented surface modification scheme is reported employing Ta2O5 membrane which covers IrO2 electrode in response to H+ and eliminating redox species interference. Evidence shows that H+ can pass through Ta2O5 films and react with IrO2/Pt electrodes due to proton-electron double injection. A Ta2O5 membrane, an ionic conductor with an insulating property, blocks the transport of electrons generated from oxygen perturbation in the solution. The conduction of both electrons and protons preserve the current continuity across the interface. Owing to proton-electron double injection, IrO2 will be reduced to Ir(OH)(3) during pH detection. The [IrO2]/[Ir(OH)(3)] will remain constant and therefore the Nernstian electrode potential performs stably as a function of pH (-59.447 to -59.504 mV/pH, 2< pH <13). In addition, the proposed pH microsensor displayed high ion selectivity with respect to K+, Na+, and Li+, with log K-H,K-M values (similar to-12.4) and has a working lifetime over one week. (C) 2013 Elsevier B.V. All rights reserved.
An electrochemical dopamine sensor with a CMOS detection circuit
(2008-07-01)
Chan, Feng-Lin
;
Chang, Wen-Ying
;
Kuo, Li-Min
;
Lin, Chih-Heng
;
Wang, Shi-Wei
This paper presents the integration of interdigitated microelectrodes and a CMOS circuit for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with a gap of 3 mu m are fabricated by the lift-off technique. The CMOS sensing circuit has a current gain of 10, an integrating capacitor of 4 pF, and a measured dynamic range of 60 dB. The applied reduction and oxidation potentials are determined by voltammetry at about -0.2 V and 0.6 V, respectively. The measured collection efficiency can reach up to 84%. The produced oxidation current with respect to dopamine concentration averages 0.44 nA mu M(-1).
An electrochemical dopamine sensor with CMOS detection circuit
(2007-01-01)
Zhan, Feng-Lin
;
Kuo, Li-Min
;
Wang, Shi-Wei
;
Lu, Michael S. -C.
;
Chang, Wen-Ying
This paper presents the use of interdigitated microelectrodes as the platform for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with gaps ranging between 3 gm to 7 gm are fabricated by the lift-off technique. The reduction and oxidation potentials for dopamine are determined by voltammetry using the fabricated microelectrodes. A CMOS sensing circuit is used to amplify the electrochemical current produced by the working electrodes. Experimental result shows that for a dopamine concentration of 10 mu M the measured current value is 11 pA.
Sealing Bump With Bottom-Up Cu TSV Plating Fabrication in 3-D Integration Scheme
(2013-05-01)
Chiang, Cheng-Hao
;
Kuo, Li-Min
;
Hu, Yu-Chen
;
Huang, Wen-Chun
;
Ko, Cheng-Ta
A sealing bump approach for the simplification of the conventional bottom-up copper through-silicon via (TSV) plating process flow is developed to reduce the process steps and increase the throughput without sacrificing the structure integrity and electrical performance. In this approach, TSV and bump formation can be achieved simultaneously through the bottom-up plating. Results from the analysis reveal excellent electrical characteristics and quality examination, which indicate that the proposed approach may be a good candidate for the TSV fabrication in 3-D integration.