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Ren N.,Jiangsu University | Liu Z.,Jiangsu University | Wang Q.,Jiangsu University | Wang Q.,CAS Shanghai State Key Laboratory of Transducer Technology
Physics Letters, Section A: General, Atomic and Solid State Physics

Flat, B-doped, low-stress and non-stress polysilicon (poly-Si) thin films were deposited by low pressure chemical vapor deposition (LPCVD). X-ray diffraction (XRD), combined with atomic force microscopy (AFM) and Raman system, UV-Raman measurements and spectroscopic ellipsometry, was used to study the microstructure, the morphology and optical properties of the films. The results indicate that the surface roughness is related to the grain size and the change in the microstructure. The B-doped poly-Si shows a tensile stress, while the flat poly-Si shows a high compressive stress. The bandgap of the B-doped poly-Si is the narrowest because of its most disordered microstructure. © 2015 Elsevier B.V. Source

Li X.,CAS Shanghai State Key Laboratory of Transducer Technology | Lee D.-W.,Chonnam National University
Measurement Science and Technology

This topical review is focused on microcantilever-based sensing and probing functions that are realized by integrating a mechanically compliant cantilever with self-sensing and self-actuating elements, specific sensing materials as well as functionalized nano-tips. Such integrated cantilever devices have shown great promise in ultra-sensitive applications such as on-the-spot portable bio/chemical detection and in situ micro/nanoscale surface analysis and manipulation. The technical details of this review will be given in a sequence of cantilever sensors and, then, cantilever-tip probes. For the integrated cantilever sensors, the frequency-output style dynamic cantilevers are described first, with the contents including optimized resonance modes, sensing-group-modified nanostructures for specific bio/chemical mass adsorption and nanoscale sensing effects, etc. Thereafter, the static cantilever sensors for surface-stress detection are described in the sequence of the sensing mechanism, surface modification of the sensitive molecule layer and the model of specific reaction-induced surface-energy variation. After technical description of the cantilever sensors, the emphasis of the review moves to functionalized nano-tip equipped cantilever-tip probing devices. The probing functions are not only integrated on the cantilever but also integrated at the sharp apex of the tip. After description of single integrated cantilever probes and their applications in surface scanning and imaging, arrayed cantilever-tip devices and their simultaneous parallel operation for high throughput imaging and nanomechanical data storage are also addressed. With cantilever-tip probes as key elements, micro-analysis instruments are introduced that can be widely used for macro/nanoscale characterizations. © 2012 IOP Publishing Ltd. Source

Wang Q.,Jiangsu University | Zhang J.,Jiangsu University | Yuan S.,Jiangsu University | Li X.,CAS Shanghai State Key Laboratory of Transducer Technology
Applied Physics Letters

Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications. This paper mainly focuses on the electrical properties of a few layers of graphene (FLG). The I-V curves of the FLG devices pass though the origin, but the relationship between the voltage and current is nonlinear. This phenomenon may be due to tunneling current when voltage is applied to the FLG. Also, charged impurities on the sample cause shifts in the maximum resistance point in FLG R-V curves, with fewer graphene layers corresponding to larger changes in resistance. © 2012 American Institute of Physics. Source

Tao B.,CAS Shanghai State Key Laboratory of Transducer Technology | Tao B.,Qiqihar University | Zhang J.,CAS Shanghai State Key Laboratory of Transducer Technology | Hui S.,CAS Shanghai State Key Laboratory of Transducer Technology | And 2 more authors.
Electrochimica Acta

A novel electrochemical methanol sensor based on a catalytic electrode of palladium-nickel/silicon nanowires (Pd-Ni/SiNWs) is presented in this paper. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electrochemical methods are employed to investigate the Pd-Ni/SiNWs electrode materials. These nanocomposite materials exhibit a highly ordered, wire-like structure with a wire length of ∼50 μm and a wire diameter ranging from 100 to 300 nm. The substrate has good electrocatalytic activity towards the oxidation of methanol in alkaline solutions. The performances of the prototype sensor are characterized by cyclic voltammetry and fixed potential amperometry techniques. In a 1 mol L-1 KOH solution containing different methanol concentrations, the sensor exhibits a good sensitivity of 1.96 mA mmol-1 L cm-2 with R2 = 0.99 and the corresponding detection limit of 18 μmol L-1 (signal-to-noise ratio = 3, S/N = 3) for cyclic voltammetry. Meanwhile, the electrode also displays a sensitivity of 0.48 mA mmol-1 L cm-2 with R2 = 0.98 and the corresponding detection limit of 25 μmol L-1 (S/N = 3) for a fixed potential amperometry at -0.3 V versus an Ag/AgCl reference electrode. The results demonstrate that the Pd-Ni/SiNWs catalytic electrode has potential as an efficient and integrated sensor for methanol detection. © 2010 Elsevier Ltd. All rights reserved. Source

Liu Q.,Zhejiang University | Liu Q.,CAS Shanghai State Key Laboratory of Transducer Technology | Wu C.,Zhejiang University | Cai H.,Zhejiang University | And 4 more authors.
Chemical Reviews

A biosensor is an analytical device that can be used for detecting analytes and combines a biological component with a physicochemical detecting transducer. In recent years, biosensors have rapidly expanded and evolved in many new fields such as molecularly sensitive receptors, biomimetic sensors, and nanotechnologies. In contrast to molecule-based approaches, cell-based biosensors have a broad spectrum of detection capabilities. Moreover, in addition to analyte sensing and detecting, cell-based biosensors can provide the advantages of rapid and sensitive analysis for in situ monitoring with cells. Cells naturally encapsulate molecular sensor arrays. Enzymes, receptors, and ion channels, all with a stable status, could respond to their corresponding analytes via a native cellular mechanism. Source

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