Critical Assessment on Modeling and Design of Non-Faradaic CMOS Electrochemical Sensing

To assist the design process of non-Faradic electrochemical sensors in realistic biological media, we examine multiple types of sensing operations in polyelectrolytes. By comparing the quasi-static transconductance, impedance spectroscopy, and capacitance-voltage (CV) measurements, we assess the physical contributions from the double layer composition, overall solution resistance, and sensing surface potential under various poly-electrolytic molarities. The mixture of NaCl and MgCl2 is chosen for illustration to provide insight into circuit model parameters for non-Faradaic sensing. Our finding also shed light on the dynamics of double-layer competition and correlation, which is critical for understanding the physical phenomena occurring at the sensing interface, and accurately interpreting sensor data.