Browsing by Author "Sheu, J. -T."

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A possibility of detection of the non-charge based analytes using ultra-thin body field-effect transistors
(2008-07-15)
Sheu, J. -T.
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Chen, C. C.
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Chang, K. S.
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Li, Y. -K.
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材料科學與工程學系奈米科技碩博班
Ultra-thin body of p-type field-effect transistors were developed as transducer for biosensors. Changes of conductance resulted from the changes of the surface potentials of ultra-thin body field-effect transistors (UTB-FETs) due to surface chemical modifications were demonstrated. The channel surface of UTB-FETs were modified with N-[3-(trimethoxysilyl)propyl]ethylenediamine (AEAPTMS) and then gold nanoparticles (AuNPs) to immobilize the bio-component, the genetically engineered Delta(5)-3-ketosteroid isomerase (Art_KSI) or the Art_KSI conjugated with charged reporter (Art_KSI_mA51). The binding of charge-based molecules or nanoparticles has been demonstrated to strongly affect the conductivity of UTB-FETs: the increase or decrease of the conductance depends on the polarity of the immobilized molecules or nanoparticles. A new protocol involving the detection of a non-charged analyte relied on the competitive binding of analyte (19-norandrostendione) and a charged reporter (mA51) with KSL When exposed to a 19-norandrostendione solution (10 mu M), the conductance of Art_KSI_mA51-modified UTB-FET increased by 265 nS (similar to 12%). On the other hand, conductance of Art_KSI_modified UTB-FET showed no distinct change under the same detection conditions. (c) 2008 Elsevier B.V. All rights reserved
Fabrication and field-emission characteristics of TiN nanorods with a concave top surface
(2008)
Chen, Te-Ming
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Hung, Jui-Yi
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Pan, Fu-Ming
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Chang, L.
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Sheu, J. -T.
Well-ordered titanium nitride nanorods were fabricated by reactive ion etch using titanium oxide nanodots as the mask, which were prepared using the anodic aluminum oxide templation method. The TiN nanorods exhibited a concave top surface with a protruding edge. Due to the protruding top edge and a high aspect ratio, the TiN nanorods showed a low turn-on voltage of 1.6 V/mu m. The ellipsoidal cylinder model was used to evaluate the field-enhancement effect of the protruding edge, and an underestimation by similar to 26% was found as compared with the enhancement factor derived from the Fowler-Nordheim plot. (C) 2008 The Electrochemical Society.
Localized Joule Heating As a Mask-Free Technique for the Local Synthesis of ZnO Nanowires on Silicon Nanodevices
(2011-11-01)
Chen, C. C.
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Lin, Y. S.
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Sang, C. H.
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Sheu, J. -T.
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材料科學與工程學系奈米科技碩博班
We report a mask-free technique for the local synthesis of ZnO nanowires (NWs) on polysilicon nanobelts and polysilicon NW devices. First, we used localized joule heating to generate a poly(methyl methacrylate) (PMMA) nanotemplate, allowing the rapid and self-aligned ablation of PMMA within a short period of time (ca. S mu s). Next, we used ion-beam sputtering to prepare an ultrathin Au film and a ZnO seed layer; a subsequent lift-off process left the seed layers selectively within the PMMA nanotemplate. Gold nanoparticles and ZnO NWs were formed selectively in the localized joule heating region.