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Open AccessArticle

Sensing Responses Based on Transfer Characteristics of InAs Nanowire Field-Effect Transistors

1
Centre for Advanced Nanotechnology, University of Toronto, 170 College Street, Toronto, ON M5S 3E4, Canada
2
Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, ON M5S 3E4, Canada
3
Defence Research and Development Canada Suffield, Medicine Hat, AB T1A 8K6, Canada
*
Author to whom correspondence should be addressed.
Sensors 2017, 17(7), 1640; https://doi.org/10.3390/s17071640
Received: 1 June 2017 / Revised: 1 July 2017 / Accepted: 13 July 2017 / Published: 16 July 2017
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Canada 2017)
Nanowire-based field-effect transistors (FETs) have demonstrated considerable promise for a new generation of chemical and biological sensors. Indium arsenide (InAs), by virtue of its high electron mobility and intrinsic surface accumulation layer of electrons, holds properties beneficial for creating high performance sensors that can be used in applications such as point-of-care testing for patients diagnosed with chronic diseases. Here, we propose devices based on a parallel configuration of InAs nanowires and investigate sensor responses from measurements of conductance over time and FET characteristics. The devices were tested in controlled concentrations of vapour containing acetic acid, 2-butanone and methanol. After adsorption of analyte molecules, trends in the transient current and transfer curves are correlated with the nature of the surface interaction. Specifically, we observed proportionality between acetic acid concentration and relative conductance change, off current and surface charge density extracted from subthreshold behaviour. We suggest the origin of the sensing response to acetic acid as a two-part, reversible acid-base and redox reaction between acetic acid, InAs and its native oxide that forms slow, donor-like states at the nanowire surface. We further describe a simple model that is able to distinguish the occurrence of physical versus chemical adsorption by comparing the values of the extracted surface charge density. These studies demonstrate that InAs nanowires can produce a multitude of sensor responses for the purpose of developing next generation, multi-dimensional sensor applications. View Full-Text
Keywords: nanowire; sensor; field-effect transistor; InAs; adsorption nanowire; sensor; field-effect transistor; InAs; adsorption
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MDPI and ACS Style

Tseng, A.C.; Lynall, D.; Savelyev, I.; Blumin, M.; Wang, S.; Ruda, H.E. Sensing Responses Based on Transfer Characteristics of InAs Nanowire Field-Effect Transistors. Sensors 2017, 17, 1640.

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