Next Article in Journal
Application of a Fluorescent Probe for the Online Measurement of PM-Bound Reactive Oxygen Species in Chamber and Ambient Studies
Next Article in Special Issue
A LAPS-Based Differential Sensor for Parallelized Metabolism Monitoring of Various Bacteria
Previous Article in Journal
Gas Sensing Properties of Perovskite Decorated Graphene at Room Temperature
Previous Article in Special Issue
InGaN as a Substrate for AC Photoelectrochemical Imaging
Open AccessArticle

Modeling of the Return Current in a Light-Addressable Potentiometric Sensor

1
Department of Biomedical Engineering, Tohoku University, 6-6, Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
2
Department of Electronic Engineering, Tohoku University, 6-6, Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
3
Frontier Research Institute of Interdisciplinary Sciences, Tohoku University, 6-3 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
*
Author to whom correspondence should be addressed.
Sensors 2019, 19(20), 4566; https://doi.org/10.3390/s19204566
Received: 24 September 2019 / Revised: 17 October 2019 / Accepted: 18 October 2019 / Published: 21 October 2019
A light-addressable potentiometric sensor (LAPS) is a chemical sensor with a field-effect structure based on semiconductor. Its response to the analyte concentration is read out in the form of a photocurrent generated by illuminating the semiconductor with a modulated light beam. As stated in its name, a LAPS is capable of spatially resolved measurement using a scanning light beam. Recently, it has been pointed out that a part of the signal current is lost by the return current due to capacitive coupling between the solution and the semiconductor, which may seriously affect the sensor performance such as the signal-to-noise ratio, the spatial resolution, and the sensitivity. In this study, a circuit model for the return current is proposed to study its dependence on various parameters such as the diameter of contact area, the modulation frequency, the specific conductivity of the solution, and the series resistance of the circuit. It is suggested that minimization of the series resistance of the circuit is of utmost importance in order to avoid the influence of the return current. The results of calculation based on this model are compared with experimental results, and its applicability and limitation are discussed. View Full-Text
Keywords: light-addressable potentiometric sensor; LAPS; chemical imaging sensor; field-effect sensor light-addressable potentiometric sensor; LAPS; chemical imaging sensor; field-effect sensor
Show Figures

Figure 1

MDPI and ACS Style

Yoshinobu, T.; Sato, D.; Guo, Y.; Werner, C.F.; Miyamoto, K.-I. Modeling of the Return Current in a Light-Addressable Potentiometric Sensor. Sensors 2019, 19, 4566.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop