The fabrication of nano porous silicon, nPSi, using alkali etching process has been studied and carried out. The surface chemistry of anisotropic etching of n-type Si-wafer is reviewed and the anisotropic chemical etc...The fabrication of nano porous silicon, nPSi, using alkali etching process has been studied and carried out. The surface chemistry of anisotropic etching of n-type Si-wafer is reviewed and the anisotropic chemical etching of silicon in alkaline solution using wetting agents is discussed. Transformation of crystallographic plane of n-Si (211) to nPSi (100) has occurred on using n-propanol as wetting agent. The rate of pore formation was 0.02478 - 0.02827 μm/min, which was heavily dependent upon the concentration of the etchant containing wetting agents, allowing patterned porous silicon formation through selective doping of the substrate. A particle size of 15 nm for porous nano-silicon was calculated from the XRD data. Porosity of PS layers is about 10%. Pore diameter and porous layer thickness are 0.0614 nm and 16 μm, respectively. The energy gap of the produced porous silicon is 3.3 eV. Furthermore, the combination of PS with Congo Red, which are nanostructured due to their deposition within the porous matrix is discussed. Such nano compounds offer broad avenue of new and interesting properties depending on the involved materials as well as on their morphology. Chemical route was utilized as the host material to achieve pores filling. They were impregnated with Congo Red, which gave good results for the porous silicon as a promising pH sensor.展开更多
文摘The fabrication of nano porous silicon, nPSi, using alkali etching process has been studied and carried out. The surface chemistry of anisotropic etching of n-type Si-wafer is reviewed and the anisotropic chemical etching of silicon in alkaline solution using wetting agents is discussed. Transformation of crystallographic plane of n-Si (211) to nPSi (100) has occurred on using n-propanol as wetting agent. The rate of pore formation was 0.02478 - 0.02827 μm/min, which was heavily dependent upon the concentration of the etchant containing wetting agents, allowing patterned porous silicon formation through selective doping of the substrate. A particle size of 15 nm for porous nano-silicon was calculated from the XRD data. Porosity of PS layers is about 10%. Pore diameter and porous layer thickness are 0.0614 nm and 16 μm, respectively. The energy gap of the produced porous silicon is 3.3 eV. Furthermore, the combination of PS with Congo Red, which are nanostructured due to their deposition within the porous matrix is discussed. Such nano compounds offer broad avenue of new and interesting properties depending on the involved materials as well as on their morphology. Chemical route was utilized as the host material to achieve pores filling. They were impregnated with Congo Red, which gave good results for the porous silicon as a promising pH sensor.
文摘通过浸涂法在钨金属丝上涂敷氧化钨氢离子敏感膜，制备了氧化钨H＋选择性电极，采用尿素改性聚乙烯醇作为参比电极的固态薄膜材料并进行KCl掺杂，经Nafion膜进行修饰后制备了固态参比电极.利用自制的氧化钨pH电极与固态参比电极制成pH电化学传感器，该传感器具有良好的响应电位E-pH线性函数关系，响应范围为pH2~pH11.响应灵敏度与氧化钨的热处理温度有关，200℃热处理后的响应灵敏度为52.81 mV/pH，响应时间与氧化钨敏感膜、测试溶液pH值以及溶液温度有关.在pH2→pH11→pH2循环测试过程中，传感器的滞后效应较小.该传感器有良好的选择性，响应行为不受Na＋、F-等常见离子的影响，但是受到氧化还原性的NO-3、I-等离子的干扰.传感器内阻很低为22.8 kΩ，远小于玻璃pH计的内阻（1×109Ω）.该传感器在各种饮料中具有较高测量精度，与玻璃pH计的测量值进行对比，两者的差值在（-0.06 pH，＋0.15pH）范围内.在10-5M→10-1M柠檬酸溶液中，传感器的响应电位与溶液浓度存在良好的线性关系，响应时间小于1 min.
