Ionization Gas Sensor using Suspended Carbon Nanotube Beams.

Shivaram Arunachalam,Ricardo Izquierdo,Frederic Nabki

doi:10.3390/s20061660

Shivaram Arunachalam, Ricardo Izquierdo + Show 1 more

Open Access

https://doi.org/10.3390/s20061660

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Abstract

An ionization sensor based on suspended carbon nanotubes (CNTs) was presented. A suspended CNT beam was fabricated by a low-temperature surface micromachining process using SU8 photoresist as the sacrificial layer. Application of a bias to the CNT beam generated very high non-linear electric fields near the tips of individual CNTs sufficient to ionize target gas molecules and initiate a breakdown current. The sensing mechanism of the CNT ionization sensor was discussed. The sensor response was tested in air, nitrogen, argon, and helium ambients. Each gas demonstrated a unique breakdown signature. Further, the sensor was tested with gaseous mixtures. The sensor exhibited good long-term stability and had comparable performance to other reported CNT-based ionization sensors in literature, which use high-temperature vapor deposition methods to grow CNTs. The sensor notably allowed for lower ionization voltages due to its reduced ionization gap size.

Highlights

Carbon nanotube (CNT)-based gas sensors have been the subject of much research in the past few decades owing to their excellent electrical and mechanical properties
We presented an ionization gas sensor based on suspended single-walled CNTs that techniques are not suited to the integration of the sensor with a wide range of substrates, which can were arranged horizontally, instead of being vertically aligned like previously mentioned publications
We presented ionization gas sensor based on suspended single-walled

Summary

Introduction

Carbon nanotube (CNT)-based gas sensors have been the subject of much research in the past few decades owing to their excellent electrical and mechanical properties. Device designs have been proposed to develop gas sensors based on CNTs with high-performance metrics [5]. CNT-based sensors have overcome these drawbacks and have proven to be excellent gas sensing elements [10]. Suspended chemical CNT chemical gas sensors have been previously fabricated [11,12]. Chikkadi et al fabricated a NO2 sensor using a single suspended CNT across prefabricated electrodes. Suspended chemical CNT sensors have been used to sense humidity [14] with minimal hysteretic effects due to the mitigation of substrate effects [15]

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