Lanthanum fluoride (LaF) and other rare-earth halides are commonly used in sensor and optical equipment. A deep eutectic solvent (DES) based LaF passivated porous silicon (PS) sensor for sensing the pH of buffer solution has been fabricated in this research. An electrochemically etched PS structure has been prepared and passivated with novel DES-based LaF to fabricate pH sensor. For the deposition of LaF thin film to create heterostructure devices, a variety of complex and costly processes have been employed. In a quest to find a facile technique to fabricate a pH sensor, this research presents the justification of sensing characteristics of DES-based spin-deposited LaF/PS structure. Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses both supported the almost stoichiometric and highly crystalline nature of LaF. Scanning electron microscopy (SEM) was used to confirm the uniform morphological structure. The sensing characteristics of fabricated pH sensors have been confirmed by studying the capacitance-voltage (CV) characteristics of prepared structure in a different buffer solution with different pH values. From the experimental results, it was observed that DES-based LaF passivated PS structure shows voltage shift at the inflexion point of CV characteristics for different pH solutions. In light of this, it can be said that a pH sensor for sensing the pH levels of any buffer solution may be fabricated by depositing novel DES-based LaF both inside the pores of PS and on top of it using the spin coating approach.

中文翻译：

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基于低共熔溶剂的新型化学路线制备 LaF3 钝化多孔硅 pH 传感器

氟化镧 (LaF) 和其他稀土卤化物通常用于传感器和光学设备。本研究制造了一种基于 LaF 钝化多孔硅 (PS) 的深共晶溶剂 (DES) 传感器，用于传感缓冲溶液的 pH 值。制备了电化学蚀刻的 PS 结构，并用新型 DES 基 LaF 钝化，以制造 pH 传感器。为了沉积 LaF 薄膜以制造异质结构器件，采用了各种复杂且昂贵的工艺。为了寻找一种简便的技术来制造 pH 传感器，本研究提出了基于 DES 的旋转沉积 LaF/PS 结构的传感特性的合理性。能量色散 X 射线光谱 (EDS) 和 X 射线衍射 (XRD) 分析均支持 LaF 的几乎化学计量和高度结晶性质。使用扫描电子显微镜（SEM）来确认均匀的形态结构。通过研究所制备的结构在不同pH值的缓冲溶液中的电容-电压(CV)特性，证实了所制造的pH传感器的传感特性。从实验结果可以看出，基于 DES 的 LaF 钝化 PS 结构在不同 pH 溶液的 CV 特性拐点处表现出电压变化。有鉴于此，可以说，通过使用旋涂方法在 PS 孔内部和顶部沉积新型 DES 基 LaF，可以制造用于感测任何缓冲溶液 pH 水平的 pH 传感器。