【作者】 石晶；

【导师】 王连卫； 彭晖；

【作者基本信息】 华东师范大学 ， 微电子学与固体电子学， 2011， 博士

【摘要】 三维结构材料的制备和应用已经引起人们极大关注,而硅基三维结构材料更是因为具有与传统集成电路工艺的兼容性以及与体材料相比所具备的独特物理与化学特性,成为制备微型电化学传感与能源器件最理想的材料。本文以电化学刻蚀技术制备的硅基微通道板为基础,开展了如下几个方面的研究工作：1.论文首先介绍了利用光辅助电化学刻蚀技术制备硅基微通道板的方法。工艺中实验参数如刻蚀溶液浓度,光照,偏压和温度也被进一步优化。在选定条件下制得的硅基微通道样品具备良好表面形貌,大的比表面积和高深宽比,并可以和衬底自分离,可作为新型三维材料应用于各个领域。2.基于竖直排列的镀镍硅基微通道板和在其表面沉积的高度分散的钯纳米粒子,制备了一种高灵敏度的电流型乙醇电化学传感器。钯修饰的镀镍硅基微通道板电极的表面形貌由扫描电子显微镜(SEM)和X射线衍射图样(XRD)表征分析。钯/镍/硅基微通道板电极对乙醇的电化学探测性能通过循环伏安法和电流测定法进行研究。这种具备三维结构的电极对于乙醇在0.10 mol L-1的氢氧化钾溶液中的氧化具有很高的催化活性。在-0.10 V的测量电位下,钯/镍/硅基微通道板电极显示了很高的灵敏度,可以达到0.992 mA mM-1 cm-2,计算得到的检测下限为16.8μM。检测线性范围高达60mmolL-1线性相关系数为0.998。它同时还具有良好的电催化性能,快速响应以及高稳定性和可重复性。3.利用电化学方法制备了过氧化聚吡咯修饰的钯/镍/硅微通道板电极,并应用于葡萄糖传感器,具备相当多的突出优势,例如较高的灵敏度,良好的稳定性和重复性以及快速响应。过氧化聚吡咯薄膜的修饰提高了传感器的选择性,并有效抑制了常见干扰物质如尿酸和抗坏血酸氧化所引起的干扰信号。在+0.08 V的电压下,可以获得0.37 mA mM-1 cm-2的高灵敏度,检测下限为2.06μM。线性检测的浓度范围为1 mM到24 mM,线性相关系数为0.997。此外,由于修饰了过氧化聚毗咯薄膜,有效抑制了常见干扰物质如尿酸和抗坏血酸所引起的干扰信号,因此所制备的电极具有很强的抗干扰能力。这种新型电极在葡萄糖的非酶检测方面具有巨大的潜力。4.本部分首先研究了燃料电池的现状和存在的主要问题,利用制备好的硅基微通道开发新型乙醇燃料电池。三维阵列中合适的通道尺寸和高多孔度增加了活性点位,增强了反应物和产物的质量输运,因此,能够加速快速电子转移,改善催化效率。在钯/镍/硅基微通道板上,乙醇的氧化电压负移,并且峰值电流密度高于平面的钯/镍/硅结构。这些结果显示了微通道结构在增强乙醇氧化活性方面的重要作用。利用计时电流法评估了钯/镍/硅基微通道板的稳定性。分别研究不同氢氧化钾浓度和不同乙醇浓度下电极对乙醇氧化的催化特性,并探讨了反应机制,为构建高功率的直接乙醇燃料电池提供了有益的基础性工作。5.电化学刻蚀技术不只可以用来制备硅基微通道板,还可以制备具有设定深度的多孔硅结构,并通过扩散形成三维PN结。三维PN结可用作新型能量转换装置,广泛适用于高能物理,洁净能源,以及材料测试。利用阳极氧化的电化学刻蚀是一种非常优良的构造三维PN结的方法。然而,P型硅相邻两个孔之间的孔壁厚度往往太薄,难以适应随后扩散的技术需求。在本部分中,脉冲电流被用于制造理想的具有较厚的侧壁的P型微结构。基于该新颖结构的三维PN结在光伏能量转换方面具有极大的潜力。通过将三维PN结应用在太阳能电池中,光子可以得到再次吸收的机会。因此,电学参数例如输出电流和能量转换效率可以被大大改善。这一理论的可行性通过Matlab仿真结果验证。而且常见的加工工艺使得这一制备技术无论在实验室还是在工业上都能得到广泛应用,因此这是一种不需要额外添加投资而获得更高效率的有效方法。综上所述,利用电化学刻蚀技术制备的硅基微通道板构成的电极具有优良的催化性能和稳定性,在电化学传感器和燃料电池中具有相当大的应用潜力,对发展可集成的新型器件具有重要意义。而同样利用电化学刻蚀方法得到的三维PN结也为新型太阳能电池的开发打下了良好的基础,为微电子机械系统加工技术在能源和传感器领域的应用提供了全新的切入点。具有一定的创新性和科研价值,它的产业化必将带来巨大的社会和经济效益。更多还原

【Abstract】 The fabrication and application of three-dimensional materials have attracted tremendous attention. Silicon based three-dimensional materials have become the best choice to fabricate micro-electrochemical sensor and energy device arising from their unique properties in physics and chemistry compared with bulk materials and compatibility with silicon IC technology. This thesis focuses on silicon micro-channel plate prepared by electrochemical etching and the main works are listed as following:First, the method of the fabrication of silicon micro-channel plate by using the photo-electrochemical technology is described. The experimental parameters such as concentration of etchant, illumination, bias voltage and etching temperature are further optimized. Samples of silicon micro-channel plate fabricated under the selected conditions have good surface topography, large active area and high aspect ratio. The micro-channel layer can be separated from substrate automatically. The silicon micro-channel plate could be applied in various fields as novel three-dimensional material.A sensitive amperometric ethanol sensor composed of highly dispersed palladium nanoparticles on the vertically aligned nickel coated silicon microchannel plate (MCP) has been constructed. The morphology of the palladium modified nickel coated silicon MCP electrode was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The performance of the Pd/Ni/Si MCP electrode for the electrochemical detection of ethanol was investigated by cyclic voltammetry and amperometry. The electrode with three dimensional structure shows high catalytic activity towards the oxidation of ethanol in 0.10 M KOH solution. At an applied potential of-0.10 V, the Pd/Ni/Si MCP electrode shows a high sensitivity of 0.992 mA mM-1 cm-2 and the detection limit is 16.8μM. The linear range is up to 60 mM with a linear correlation coefficient of 0.998.It also possesses excellent electrocatalytic properties,rapid response,as well as good stability and repeatability.The OPPy-Pd/silicon MCP electrode fabricated electrochemically boasts a number of advantages such as high sensitivity,good stability,reproducibility,and quick response.Excellent selectivity is rendered by the OPPy film and signals arising from oxidation of common interferences such as UA and AA can be effectively suppressed. At a potential of+0.08 V,good sensitivity of 0.37 mA mM-1 cm-2 and detection limit of 2.06μM are attained. The linear range is up to 24 mM with a linear correlation coefficient of 0.997. Furthermore, the electrode is highly resistant to interfering substances because the effects of common coexisting substances can be effectively eliminated by the OPPy film and the response in the current to interferences on the electrode surface is almost negligible. This novel electrode has great potential application in nonenzymatic detection of glucose.We developed an ethanol fuel cell based on silicon micro-channel plate. The suitable spatial dimension and high porosity in this three-dimensional array can increase the active sites and enhance the mass transfer of reactants or products, thereby accelerating fast electron transfer and improving the catalyst efficiency. The onset potential for ethanol oxidation shifts negatively on Pd/Ni/Si MCP, and the current density peak is higher than that of planar Pd/Ni/Si. These results reveal that the microchannel structure plays an important role in the enhanced activity of ethanol oxidation. The stability of the Pd/Ni/Si MCP is evaluated by chronoamperogram. The electrocatalytic performance of prepared electrode for ethanol oxidation was investigated by varying concentrations of KOH and ethanol in order to understand the mechanism.The electrochemical etching technology can not only be used to prepare silicon-based micro-channel plate, but also be applied to fabricate porous silicon structure with given depth. The three-dimensional p-n junction based on porous silicon structure is formed by diffusion which can be used as novel energy conversion device adopted in high energy physics, clean energy power source and material test. The electrochemical etching process utilizing anodization has been described as a recommendable method to fabricate three-dimensional structure for p-n junction. However, the thickness of sidewall between two adjacent pores in the structure is usually too thin for p-type silicon to accord with technological requirement of following diffusion. In this section, pulse current was employed to manufacture satisfactory microstructure p-type silicon with thick sidewall.The 3D p-n junction based on this novel structure is promising for application in photovoltaic energy conversion and detection. By applying 3D p-n junction in solar cell,photons acquire an opportunity for secondary absorption. Therefore,electrical parameters such as output current and energy conversion efficiency are greatly improved. The feasibility of the theory is proved by the results of Matlab simulations.Furthermore,common fabrication process facilitates their applications both at laboratory and industrial levels, so it is an effective method which can yield higher efficiency without a large number of additional investments.In conclusion,electrodes constructed by silicon-based micro-channel plate have high potential in electrochemical sensors and fuel cells owing to superior electrocatalytic properties and stability.It is of great significance for development of novel integrated device.The three-dimensional p-n junction which is also obtained by electrochemical etching method has laid good foundation for the improvement of solar cell. The works in this thesis provide new entry point for the application of micro electro mechanical system technology in energy source and sensor field. The industrialization of this research with innovative and scientific value will bring huge social and economic benefits.更多还原