Correlation of Low-Frequency Noise to the Dynamic Properties of the Sensing Surface in Electrolytes

Abstract

Low-frequency noise (LFN) is of significant implications in ion sensing. As a primary component of LFN for ion sensing in electrolytes, the solid/liquid interfacial noise remains poorly explored especially regarding its relation to the surface binding/debinding dynamic properties. Here, we employ impedance spectroscopy to systematically characterize this specific noise component for its correlation to the dynamic properties of surface protonation (i.e., hydrogen binding) and deprotonation (i.e., hydrogen debinding) processes. This correlation is facilitated by applying our recently developed interfacial impedance model to ultrathin TiO layers grown by means of atomic layer deposition (ALD) on a TiN metallic electrode. With an excellent fitting of the measured noise power density spectra by the model for the studied TiO layers, we are able to extract several characteristic dynamic parameters for the TiO sensing surface. The observed increase of noise with TiO ALD cycles can be well accounted for with an increased average binding site density. This study provides insights into how detailed surface properties may affect the noise performance of an ion sensor operating in electrolytes.

Device Noise Reduction for Silicon Nanowire Field-Effect-Transistor Based Sensors by Using a Schottky Junction Gate

“…Downscaling SiNWFETs, aiming to increase the surface-to-volume ratio for extremely low concentration detections, inevitably leads to increase of the noise intensity dramatically. , For a SiNWFET sensor operating in electrolytes, the noise has three main components, i.e., the bulk electrolyte noise, the solid–liquid interface noise, and the SiNWFET intrinsic device noise, with the latter two being dominant. Our previous study points out that the solid–liquid interface noise can be reduced by decreasing the number of binding sites with large kinetic barriers. In this study we aim to reduce SiNWFET intrinsic device noise by replacing oxide/semiconductor interfaces with metal/semiconductor Schottky junctions.…”

In Operando Observation of Neuropeptide Capture and Release on Graphene Field-Effect Transistor Biosensors with Picomolar Sensitivity

“…Similar to association and dissociation of analyte, motion in a direction perpendicular to the sensor surface is expected to add noise as the analyte goes in and out of the Debye length. 43,44 LC-TEM, especially on functional GFET devices, appears poised to enable these investigations.…”

“…These observations provide information which is potentially valuable toward understanding the sources of noise or transients in the sensor response in a number of analyte capture strategies. Recent theoretical studies consider association and dissociation of the analytes as the only source of noise, − however the role of rotational motion of captured analyte on sensor surfaces or of variability in radius of the positional fluctuation envelope on sensor noise is yet to be investigated in detail. Similar to association and dissociation of analyte, motion in a direction perpendicular to the sensor surface is expected to add noise as the analyte goes in and out of the Debye length. , LC-TEM, especially on functional GFET devices, appears poised to enable these investigations.…”

Analysis of underwater motion noise characteristics of electrode pair towed antenna

“…Therefore, how to improve the working signal-to-noise ratio is the current research focus of underwater towed antennas [3,4,5,6,7]. Among them, the running speed of the towed antenna is an important factor affecting the signal reception, and the complex marine environment and motion state bring a variety of noise effects [8,9,10]. The introduced motion noise can be divided into motion polarization noise and motion-induced noise by different formation mechanisms.…”