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Optical Gas Sensing Properties of ZnO Nanowires

Conference paper
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Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 54)

Abstract

New breakthroughs in preparation technology have given further impulse for developing chemical sensing devices based on nanostructured ZnO. Due to their peculiar characteristics and size effects, these materials often show novel physical properties. In this work, we studied the optical properties of ZnO nanowires, synthesized via evaporation-condensation (EC) process, by room temperature photoluminescence (PL) and Time Resolved PL analysis. ZnO PL spectrum shows an UV peak, attributed to free exciton, and a broad visible band, strongly depending on the preparation conditions in the range from green to yellow. UV photoluminescence of ZnO nanowires was studied in gaseous atmosphere, targeting mainly NO2 sensing applications. Continuous wave PL shows that a reversible modification is obtained upon exposure to low concentration of NO2. The effect of interfering species like ethanol and RH% has also been studied. Time-resolved PL shows small modifications of recombination rates due to introduction of NO2 not proportional to simultaneous changes in PL intensity. This behaviour supports the idea that NO2 molecules, chemisorbed on the ZnO surface, lead to suppression of radiative states.

Keywords

Preparation Technology Room Temperature Photoluminescence Visible Emission Band Time Laser Pulse Broad Visible Band 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.SENSOR LAB, CNR – INFM & Department of Physics and ChemistryUniversity of BresciaBresciaItaly
  2. 2.CNR—INFM COHERENTIA Unity & Dipartimento di Scienze FisicheUniversity of Napoli “Federico II”NapoliItaly

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