Ting-Kai Huang

(110)-exposed gold nanocoral electrode as low onset potential selective glucose sensor.

A straightforward electrochemical deposition process was developed to grow gold nanostructures, including nanocoral, nanothorn, branched belt, and nanoparticle, on carbon electrodes by reducing HAuCl4 under constant potentials in mixtures containing CTAC and/or NaNO3. Among the nanostructures, the quasi-one-dimensional nanocoral electrode showed the highest surface area. Because of this, it provided excellent electrochemical performances in cyclic voltammetric (CV) studies for kinetic-controlled enzyme-free glucose oxidation reactions. In amperometric studies carried out at 0.200 V in PBS (pH 7.40, 0.100 M), the nanocoral electrode showed the highest anodic current response. It also offered the greatest sensitivity, 22.6 μAmM(-1)cm(-2), an extended linear range, 5.00×10(-2) mM to 3.00×10(1) mM, and a low detection limit, 1.00×10(1) μm among the electrodes investigated in this study. In addition, the glucose oxidation by the nanocoral electrode started at -0.280 V, more negative than the one of using a commercial Au electrode as the working electrode. This is attributed to the presence of exposed Au (110) surfaces on the electrode. The feature was applied to oxidize glucose selectively in the presence of ascorbic acid (AA) and uric acid (UA), common interferences found in physiological analytes. With an applied voltage at -0.100 V, the AA oxidation (started at -0.080 V) can be avoided while the glucose oxidation still provides a significant response.

A simple and low-cost method to fabricate TFTs with poly-Si nanowire channel

A very simple and low-cost scheme is proposed for fabricating thin-film transistors with poly-Si nanowire (NW) channels. In this scheme, the poly-Si NW channel is formed by cleverly employing the poly-Si sidewall spacer technique. In addition, the poly-Si NW channel is genuinely exposed to the environment after the poly-Si sidewall spacer formation in the new scheme. This unique feature, together with its simplicity and low-cost, makes this approach very suitable for applications and manufacturing of bio-logic sensing devices. Good device performance is demonstrated in this letter.

High-performance TFTs with Si nanowire channels enhanced by metal-induced lateral crystallization

Thin-film transistors with poly-Si nanowire (NW) channels enhanced by metal-induced lateral crystallization (MILC) are reported. The new device features a side-gate with self-aligned NW channels abutting the sidewalls of the gate structure. By adopting the MILC technique, the crystallinity of the NW channels is greatly enhanced, compared to those formed by solid-phase crystallization. As a result, the electrical performance of the devices could be significantly enhanced in terms of reduced subthreshold swing and threshold voltage as well as improved field-effect mobility.

Electrochemical growth of gold nanostructures on carbon paper for alkaline direct glucose fuel cell

Au nanocorals and nanoparticles were grown on carbon papers via a simple two-electrode electrochemical deposition process by reducing HAuCl4 under constant potentials in mixtures containing cetyltrimethylammonium chloride (CTAC) and/or NaNO3. Electrochemical characterizations showed that the nanocoral electrode exhibited high surface area and high electrocatalytic activity towards glucose oxidation in alkaline media. These Au nanostructures were employed as anodes and assembled with anion exchange membranes and Pt cathodes for alkaline direct glucose fuel cell (DGFC) investigations. Open-circuit voltages (OCVs) of the Au nanocoral and nanoparticle electrodes were 0.64 V and 0.61 V, and their maximum power densities were 0.847 mW cm−2 and 0.336 mW cm−2, respectively. The cells showed stable output over 5 h with a small decrease in OCV (6.9%). The electrodes could be refreshed after electrochemical reduction steps.

Growth of High-Aspect-Ratio Gold Nanowires on Silicon by Surfactant-Assisted Galvanic Reductions

A simple galvanic reduction for direct growth of Au nanowires on silicon wafers is developed. The nanowires were prepared by reacting HAuCl4aq with Sns in the presence of CTACaq (cetyltrimethylammonium chloride) and NaNO3aq, which were important to the product morphology development. The nanowire diameter was 50-100 nm, and the length was more than 20 microm.

Growth of pagoda-topped tetragonal copper nanopillar arrays.

Growth of arrays of pagoda-topped tetragonal Cu nanopillar (length 1- 6 mum; width 150 +/- 25 nm) with {100} side faces on Au/glass is achieved by a simple electrochemical reduction of CuCl(2)(aq) by Al(s) in aqueous dodecyltrimethylammonium chloride. Field-emission measurement shows that the Cu nanopillars can emit electrons (10 muA cm(-2)) at a turn-on field of 12.4 V mum(-1) with a calculated field enhancement factor of 713.

Rectangular copper nanotubes

One-dimensional Cu nanomaterials with a new morphology, rectangular copper nanotubes (copper NTs), were synthesized on a large-scale using a cetyltrimethylammonium chloride-assisted galvanic replacement reaction on rough Al substrates. In an acidic environment, Cu(II) is reduced on sharp-topped Al substrates and copper NTs 150–300 nm in diameter and 2–10 μm in length were formed through fine-tuning the reaction temperature and chemical stoichiometry. Field-emission measurement results show that the copper NTs emitting electrons at turn-on fields of 8.76 V μm−1 was observed with a field enhancement factor of 85. The superior catalytic property of copper NTs in the degradation of a methylene blue aqueous solution in the presence of H2O2 was also presented in this article.