Role of the Exposed Polar Facets in the Performance of Thermally and UV Activated ZnO Nanostructured Gas Sensors

Mohammad R. Alenezi, Abdullah S. Alshammari, K.D.G. Imalka Jayawardena, Michail Beliatis, Simon J. Henley, S.R.P. Silva

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Abstract

ZnO nanostructures with different morphologies (nanowires, nanodisks, and nanostars) were synthesized hydrothermally. Gas sensing properties of the asgrown nanostructures were investigated under thermal and UV activation. The performance of the ZnO nanodisk gas sensor was found to be superior to that of other nanostructures (Sg ∼ 3700% to 300 ppm ethanol and response time and recovery time of 8 and 13 s). The enhancement in sensitivity is attributed to the surface polarities of the different structures on the nanoscale. Furthermore, the selectivity of the gas sensors can be achieved by controlling the UV intensity used to activate these sensors. The highest sensitivity value for ethanol, isopropanol, acetone, and toluene are recorded at the optimal UV intensity of 1.6, 2.4, 3.2, and 4 mW/cm2, respectively. Finally, the UV activation mechanism for metal oxide gas sensors is compared with the thermal activation process. The UV activation of analytes based on solution processed ZnO structures pave the way for better quality gas sensors.
Original languageEnglish
JournalJournal of Physical Chemistry Part C: Nanomaterials and Interfaces
Volume117
Pages (from-to)17850−17858
ISSN1932-7447
DOIs
Publication statusPublished - 2013
Externally publishedYes

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