The floating gate, electrolyte-gated transistor (FGT) is a chemical sensing device utilizing a floating gate electrode to physically separate and electronically couple the active sensing area with the transistor. The FGT platform has yielded promising results for the detection of DNA and proteins, but questions remain regarding its fundamental operating mechanism. Using carboxylic acid-terminated self-assembled monolayers (SAMs) exposed to solutions of different pH, we create a charged surface and hence characterize the role that interfacial charge concentration plays relative to capacitance changes. The results agree with theoretical predictions from conventional double-layer theory, rationalizing nonlinear responses obtained at high analyte concentrations in previous work using the FGT architecture. Our study elucidates an important effect in the sensing mechanism of FGTs, expanding opportunities for the rational optimization of these devices for chemical and biochemical detection.

中文翻译：

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带有浮栅的电解质门控晶体管对化学传感的界面电荷贡献

浮栅，电解质门控晶体管（FGT）是一种化学传感设备，利用浮栅电极将有源传感区域与晶体管物理分离并电耦合。FGT平台在检测DNA和蛋白质方面已经产生了令人鼓舞的结果，但是有关其基本操作机制的问题仍然存在。使用暴露于不同pH值的羧酸封端的自组装单分子层（SAMs），我们创建了带电表面，因此表征了界面电荷浓度相对于电容变化的作用。结果与传统双层理论的理论预测相符，该理论合理化了先前使用FGT架构在高分析物浓度下获得的非线性响应。