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FET Devices (fet + device)
Selected AbstractsZnO Nanofiber Field-Effect Transistor Assembled by ElectrospinningJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2008Hui Wu A ZnO nanofiber field-effect transistor (FET) was assembled by electrospinning. Uniform ZnO nanofibers with a diameter of ,70 nm and length over 100 ,m were first synthesized by electrospinning. Using two paralleled electrodes as fiber collectors, we have successfully placed a single ZnO nanofiber on the electrodes, and an FET device was fabricated based on the assembled nanofiber. An electrical transport measurement was conducted on the FET device, showing that ZnO nanofibers are intrinsic n- type semiconductors. The present findings demonstrate that electrospinning can potentially be used as a straightforward and cost-effective means for the assembly of one-dimensional nanostuctures for building integrated nanodevices for various applications, such as transistors, sensors, diodes, and photodetectors. [source] GaN Nanofibers based on Electrospinning: Facile Synthesis, Controlled Assembly, Precise Doping, and Application as High Performance UV Photodetector,ADVANCED MATERIALS, Issue 2 2009Hui Wu Nitride nanofibers have been synthesized based on a simple electrospinning technique for the first time. No catalysts or templates are needed in this new synthetic method. Highly oriented GaN nanofiber arrays, as well as a high-performance UV photodetector based on single GaN nanofiber assembled FET devices, can be facilely fabricated using this technique. Precise doping of other elements into the GaN nanofibers is easy by this solution-based synthetic method. [source] Impedimetric detection of covalently attached biomolecules on field-effect transistorsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2009Ranjita GhoshMoulick Abstract A method for impedimetric detection of biomolecules with field-effect transistor (FET) arrays is presented. For biomolecular detection, the corresponding molecules such as single-stranded DNA or bovine serum albumine (BSA) were covalently immobilized to the gate structure of 16-channel open-gate FET devices. A micro spotter system was used to site-selectively attach biomolecules to selected channels out of the array. The differential transistor transfer function (TTF) of the FETs with attached biomolecules compared to free FETs was recorded. With this impedimetric technique it was possible to reliably detect biomolecules, because the recordings were not disturbed by the typical long-term drift of the sensors like in potentiometric readout mode. For transistor gates, where DNA sequences of different length were attached, small differences in the TTF spectra were detected. When BSA was covalently immobilized to the FETs clear differences in the TTF spectra were detected, which were independent on buffer pH variations around the isoelectric point of the protein. Based on the results presented in this article it can be concluded, that the TTF method detects passive components of the biomolecules like resistance and capacitance rather than surface charge effects. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Properties of Some Alkyl Substituted Phthalocyanines and Related MacrocyclesTHE CHEMICAL RECORD, Issue 4 2002Michael J. Cook Abstract This report provides an account of research undertaken at the University of East Anglia, United Kingdom, into phthalocyanine derivatives substituted at six or more of the nonperipheral sites by alkyl groups. When first prepared they were only the second series of substituted phthalocyanines known to exhibit columnar liquid crystal behaviour. The compounds also form structured films by the spin-coating technique, a formulation with potential for FET devices. The zinc metallated derivatives are photosensitisers of singlet oxygen and show good potential for applications in photodynamic therapy. A mixed cyclotetramerisation of a 3,6-dialkylphthalonitrile with a second aromatic dinitrile forms so-called 3,:,1 phthalocyanines in which three of the benzenoid rings are substituted with two alkyl groups and the fourth is substituted differently. Appropriate substituents provide amphiphilic compounds that form well-ordered films by the Langmuir-Blodgett method and self-assembly techniques. Characterisation of the films using a variety of methods is discussed and applications described. Examples of 3,:,1 phthalocyanine-like macrocycles in which one of the benzenoid rings is replaced by a heterocycle extend the range of properties exhibited. These include broadband absorption in the near infrared and, in particular cases, edge-to-face dimerisation through coordination of a pyridine nitrogen to a zinc centre in a second macrocycle. The potential for using suitably functionalised 3,:,1 phthalocyanines as building blocks for more complex structures such as liquid crystalline main-chain polymeric phthalocyanines and phthalocyanino-dehydroannulenes is described. © 2002 The Japan Chemical Journal Forum and Wiley Periodicals, Inc., Chem Rec 2: 225,236, 2002: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10028 [source] | ||||||||||