Shirale Dhammanand J, Bangar Mangesh A, Chen Wilfred, Myung Nosang V, Mulchandani Ashok
Department of Chemical and Environmental Engineering and Center for Nanoscale Science and Engineering, University of California, Riverside, CA 92521, USA.
J Phys Chem C Nanomater Interfaces. 2010 Aug 12;114(31):13375-13380. doi: 10.1021/jp104377e.
Effect of different aspect ratio (length to diameter ratio, L:D) on single polypyrrole (Ppy) nanowire based field effect transistor (FET) sensor for real time pH monitoring was studied. Ppy nanowires with diameters of ~60, ~80 and ~200 nm were synthesized using electrochemical deposition inside anodized aluminium oxide (AAO) template and were assembled using AC dielectrophoretic alignment followed by maskless anchoring on a pair of gold electrodes separated with different gap lengths. Microfabricated gold electrode patterns with gap size between 1 - 4 μm were developed by means of MEMS technique (photolithography). Using field effect transistor geometry with pair of microfabricated gold contact electrodes serving as a source and a drain, and a platinum (Pt) mesh (anchored in a microfluidic channel) was used as a gate electrode. When effect of different aspect ratio of the nanowire were compared, higher sensitivity was recorded for higher aspect ratio. The sensitivity was further improved by modulating the gate potential. These FET sensors based on single polypyrrole nanowire exhibited excellent and tunable sensitivity towards pH variations.
研究了不同长径比（长度与直径之比，L:D）对基于单聚吡咯（Ppy）纳米线的场效应晶体管（FET）传感器实时监测pH值的影响。采用电化学沉积法在阳极氧化铝（AAO）模板内合成了直径约为60、80和200nm的Ppy纳米线，并通过交流介电泳排列进行组装，随后在不同间隙长度分隔的一对金电极上进行无掩膜锚定。利用微机电系统技术（光刻）制作了间隙尺寸在1 - 4μm之间的微纳加工金电极图案。采用场效应晶体管结构，一对微纳加工的金接触电极分别作为源极和漏极，铂（Pt）网（锚定在微流体通道中）作为栅极。当比较纳米线不同长径比的影响时，长径比越高，灵敏度越高。通过调节栅极电位，灵敏度进一步提高。这些基于单聚吡咯纳米线的FET传感器对pH值变化表现出优异且可调的灵敏度。
