Control Of The Intrinsic Sensor Response To Volatile Organic Compounds With Fringing Electric Fields

Keywords

chemical sensor; fringing electric field; intrinsic sensor response; kelvin probe force microscopy; sensor selectivity; volatile organic compounds

Abstract

The ability to control surface-analyte interaction allows tailoring chemical sensor sensitivity to specific target molecules. By adjusting the bias of the shallow p-n junctions in the electrostatically formed nanowire (EFN) chemical sensor, a multiple gate transistor with an exposed top dielectric layer allows tuning of the fringing electric field strength (from 0.5 × 107 to 2.5 × 107 V/m) above the EFN surface. Herein, we report that the magnitude and distribution of this fringing electric field correlate with the intrinsic sensor response to volatile organic compounds. The local variations of the surface electric field influence the analyte-surface interaction affecting the work function of the sensor surface, assessed by Kelvin probe force microscopy on the nanometer scale. We show that the sensitivity to fixed vapor analyte concentrations can be nullified and even reversed by varying the fringing field strength, and demonstrate selectivity between ethanol and n-butylamine at room temperature using a single transistor without any extrinsic chemical modification of the exposed SiO2 surface. The results imply an electric-field-controlled analyte reaction with a dielectric surface extremely compelling for sensitivity and selectivity enhancement in chemical sensors.

Publication Date

1-26-2018

Publication Title

ACS Sensors

Volume

3

Issue

1

Number of Pages

128-134

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/acssensors.7b00754

Socpus ID

85041222240 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85041222240

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