Application And Preparation Of Metal Modified Silicon Nanowires Arrays

Recently, the nanostructured materials have become the research focus due to their unique physical and chemical properties. Nanostructured materials are playing an important role in a variety of niicro-nano devices. Among them, silicon nanowires (SiNWs) has been studied intensively due to their excellent electrical and optical properties. It is also found that the silicon modified nanowires exhibit the special and novel characteristics. Therefore, researchers prepared different metal modified nano materials as a focus study of new generation of micro-nano devices.In this work, the electrochemical glucose sensors and the direct ethanol fuel cell prototypes based on the metal-modified silicon nanowires is present. First, the silicon nanowire arrays are prepared by wet chemical etching, then the SiNWs were modified by some metals like Pd, Ni and Ag with electroless plating. Finally, the electrochemical detection sensitivity and catalytic properties of SiNWs sensors were studied by electrochemical method. The mainly works are listed as following:First, the growth and fabrication mechanism of SiNWs arrays is investigated. SiNWs arrays were prepared metal-assisted chemical etching method, which is a also known as a "top-down" technique. The dimension of SiNWs arrays prepared is 80-100μm in length and 200-400nm in diameter. The structural and morphological properties of SiNWs were characterized by SEM (Scanning Electron Microsocop) and XRD (X-Ray Diffraction) technique.Second, different metal modified SiNWs arrays structures were studied. Chemical solution method was used to deposit Pd-Ni and Ag on SiNWs arrays. The properties of Pd-Ni/SiNWs and Ag/SiNWs were examined by SEM (Scanning Electron Microsocop) and XRD (X-Ray Diffraction) technique.Thirdly, a novel electrochemical glucose sensor based on Pd-Ni/SiNWs electrode had been constructed. The developed sensors can overcome the catalyst's poisoning and unstablity, which is regarded as the common problems in current electrochemical glucose sensors. The catalytic behavior of Pd-Ni/SiNWs glucose sensor is characterized by cyclic voltammetry (CV) and fixed potential amperometry. The Pd-Ni/SiNWs electrode showed an excellent sensitivity of 190.72μAmM-lcm-2 with the detection limit (S/N ratio=3) of 2.88μM. And it also exhibits superior anti-interference properties to the species including ascorbic acid (AA), uric acid (UA) and 4-acetamidophenol (AP). All results demonstrated that this Pd-Ni/SiNWs electrode is a potential candidate for glucose detection. This sensor has superior stability, and it is easily fabricated and compatible with integrated circuits (ICs) and micro-fabrication process.At last, a prototype of direct ethanol fuel cell (DEFC) without noble metal catalyst was present in this work. The prototype consisted of Pd-Ni/SiNWs electrode as anode, and AgO/SiNWs electrode as cathode. With ethanol as the fuel, oxygen in the air as the oxidant,1M KOH medium as the electrolyte, the electrodes behaviors are characterized by electrochemical workstation. And the open circuit voltage (OCV) and short circuit current of this prototype were studied. Our work demonstrated that it is possible to develop non-Pt-based catalyst direct ethanol fuel cell.