Increasing concern on health hazard due to pollution or terrorist attacks encouraged an increasing research effort on gas sensing for real-time monitoring of all aspects of indoor and outdoor environments. Industrial requirements for a sensor are high sensitivity, high selectivity and good stability, together with low fabrication costs.

Among all possible technological approaches, conductometric gas sensors based on metal oxide semiconductors are the most promising for the development of low cost and reliable sensors. It has been confirmed that the sensitivity of metal oxide is improved as the crystallite size is decreased down to nanometer scale, thanks to the increased surface to volume ratio and the grains carriers’ depletion. Unfortunately polycrystalline metal oxides suffer from grain coalescence induced by the high operating temperatures required to enhance chemical reactions. This affects sensor stability over long-term operation. On the contrary single crystalline nanosized metal oxide are stable materials and have the dimensions and surface to volume ratio necessary to obtain high chemical sensitivity. The better stoichiometry and greater crystallinity degree compared to polycrystalline oxides make these materials very promising for a better understanding of sensing principles and the development of a new generation of chemical sensors.

After the first publication demonstrating the capability of nanowires to detect gaseous species, huge research activity was carried out as demonstrated by the high number of publications and conferences on this topic. The challenge is the integration into sensing platforms necessary for the exploitation in the sensor market. Concerning gas sensing application metal oxide nanowires demonstrate performace suited to detect chemical warfare agents (CWAs) simulants at concentrations close or lower than the toxicity values of the real CWAs. 

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/18377 must be provided.

1. Aligned carbon nanotube thin films for genosensor development
2. Structural characterisation of V2O5-TiO2 thin films deposited by RF sputtering from a Ti target with V insets