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Advances in Materials Science and Engineering
Volume 2013 (2013), Article ID 898565, 13 pages
Research Article

Characterization of Metal Oxide-Based Gas Nanosensors and Microsensors Fabricated via Local Anodic Oxidation Using Atomic Force Microscopy

1Divisão de Metrologia de Materiais, Instituto Nacional de Metrologia (INMETRO), Qualidade e Tecnologia, 25250-020 Duque de Caxias, RJ, Brazil
2Laboratório Nacional de Luz Síncrotron, Caixa Postal 6192, 13083-970 Campinas, SP, Brazil
3Departamento de Física, Universidade Federal de Minas Gerais, 30123-970 Belo Horizonte, MG, Brazil
4Instituto de Física, PPGMicro, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS, Brazil

Received 27 May 2013; Accepted 13 August 2013

Academic Editor: Bin Zhang

Copyright © 2013 Bráulio S. Archanjo 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.


This work reports on nanoscale and microscale metal oxide gas sensors, consisting of metal-semiconductor-metal barriers designed via scanning probe microscopy. Two distinct metal oxides, molybdenum and titanium oxides, were tested at different temperatures using CO2 and H2 as test gases. Sensitivities down to ppm levels are demonstrated, and the influence of dry and humid working atmospheres on these metal oxide conductivities was studied. Furthermore, the activation energy was evaluated and analyzed within working sensor temperature range. Finally, full morphological, chemical, and structural analyses of the oxides composites are provided allowing their identification as MoO3 and Ti .