Silicon-based supercapacitors are highly essential for the utilization of supercapacitor technology in consumer electronics, owing to their on-chip integration with the well-established complementary metal–oxide–semiconductor-related fabrication technology. In this study, silicon nanowalls were carved on commercially available silicon wafers by using a facile, low-cost and complementary metal–oxide–semiconductor compatible method of metal (silver)-assisted chemical etching. The electron microscopic studies of the carved out silicon nanowalls reveal that they are smooth, single crystalline and vertically aligned to their base silicon wafer. Raman and ATR-FTIR spectroscopy confirm that the surface of the silicon nanowalls has Si–O–Si bonded structures. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) studies were carried out in the organic electrolyte tetraethylammonium tetrafluroborate (NEt 4 BF 4 ) in propylene carbonate (PC). It is evident from both the CV and GCD studies that the silicon nanowalls exhibit redox peaks arising from the silver-related deep-level trap state in silicon in contact with adsorbed water and also from the oxidation of silicon and its hydrides by the water present in the electrolyte. The presence of silver in silicon nanowalls and water in the electrolyte are considered to be due to the minute amount of silver left over during its removal by HNO 3 , owing to the bunching of nanowalls and the highly moisture sensitive nature of the electrolyte, respectively. The influence of such redox peaks on capacitance and cycle life are discussed.

中文翻译：

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用于超级电容器应用的晶圆级合成硅纳米壁的电化学研究

硅基超级电容器对于超级电容器技术在消费电子产品中的应用非常重要，因为它们与完善的互补金属氧化物半导体相关制造技术的片上集成。在这项研究中，通过使用一种简便、低成本且互补的金属-氧化物-半导体兼容的金属（银）辅助化学蚀刻方法，在市售的硅晶片上雕刻了硅纳米壁。雕刻出的硅纳米壁的电子显微镜研究表明，它们是光滑的单晶，并与它们的基础硅晶片垂直对齐。拉曼光谱和 ATR-FTIR 光谱证实硅纳米壁的表面具有 Si-O-Si 键合结构。循环伏安法 (CV) 和恒电流充放电 (GCD) 研究在有机电解质四氟硼酸四乙基铵 (NEt 4 BF 4 ) 的碳酸亚丙酯 (PC) 中进行。从 CV 和 GCD 研究中可以明显看出，硅纳米壁表现出氧化还原峰，这是由于与吸附水接触的硅中与银相关的深能级陷阱状态以及硅及其氢化物被存在于其中的水氧化而产生的。电解质。硅纳米壁中银的存在和电解质中的水被认为是由于在其被 HNO 3 去除过程中留下的微量银，分别是由于纳米壁的聚束和电解质的高度湿敏性质。讨论了这种氧化还原峰对电容和循环寿命的影响。