Vanadium oxide nanotubes (VONTs) were synthesized using the V2O5 powder as precursor with dodecylamine as structure-directing template via one-step hydrothermal way. The prepared VONTs sensors exhibit excellent sensing sensitivity and superior recovery property in detecting ethanol vapor. The response to the ethanol vapor and NO2 gases confirms that the samples are of p-type behavior at 80 degrees C, which is associated with the presence of the protonated amine molecules in the VONTs. The sample changes to n-type behavior at 260 degrees C arising from the decomposition of the protonated amine molecules. The p-type VONTs have potential for development of a novel gas sensor. (c) 2012 Elsevier B.V. All rights reserved.