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Journal of Sensors
Volume 2015 (2015), Article ID 108581, 7 pages
http://dx.doi.org/10.1155/2015/108581
Research Article

Ultrasensitive NO2 Gas Sensor Based on Epitaxial Graphene

1Department of Micro- and Nanosciences, Aalto University, Micronova, Tietotie 3, 02150 Espoo, Finland
2MIKES, Tekniikantie 1, P.O. Box 9, 02151 Espoo, Finland

Received 20 November 2014; Revised 12 January 2015; Accepted 15 January 2015

Academic Editor: Marco Consales

Copyright © 2015 S. Novikov et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We report about technology of fabrication and optimization of a gas sensor based on epitaxial graphene. Optimized graphene/metal contact configuration exhibited low contact resistance. Complementary annealing of graphene sensor after each gas exposure led to significant improvement in the sensing performance. The response of the annealed sensor to the nitrogen dioxide (NO2) was tenfold higher than that of an as-fabricated graphene sensor. NO2 concentration as low as 0.2 parts per billion (ppb) was easily detectable. Devices have high signal-to-noise ratio. The detection limit of the graphene sensor was estimated to be 0.6 ppt (parts per trillion). The present technology with additional annealing improves the performance of the graphene based sensor and makes it suitable for the environmental nitrogen dioxide gas monitoring.