J B K Law and J T L Thong 2008 Nanotechnology 19 205502 doi:10.1088/0957-4484/19/20/205502
J B K Law and J T L Thong
Show affiliationsWe report a method to improve the sensitivity of a zinc oxide (ZnO) nanowire gas sensor towards ammonia (NH3) without the use of catalyst nanoparticles on the nanowire surface. This improvement is achieved by lowering the nominal carrier concentration in the as-grown ZnO nanowires. The carrier concentration in the as-grown ZnO nanowires can be tuned by treating these nanowires to either an oxidizing gas plasma or a reducing gas plasma, as observed from the measured current–voltage (I–V) characteristics response. We demonstrate that a ZnO nanowire sensor device that has been subjected to oxygen plasma treatment, thereby having a reduced carrier concentration, exhibits a sensitivity towards 0.75% NH3 gas that is improved by approximately four times. The origin of this gas sensitivity improvement is discussed based on x-ray photoelectron spectroscopy analysis results of the plasma-treated ZnO nanowires.
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
73.63.-b Electronic transport in nanoscale materials and structures
82.80.Pv Electron spectroscopy (x-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
Instrumentation and measurement
Issue 20 (21 May 2008)
Received 15 December 2007, in final form 14 March 2008
Published 14 April 2008
A Corrigendum for this article has been published in 2008 Nanotechnology 19 399801
J B K Law and J T L Thong 2008 Nanotechnology 19 205502
Alexander Stibor et al 2005 New J. Phys. 7 224
P W Tasker 1979 J. Phys. C: Solid State Phys. 12 4977
M. A. Stark et al. 2008 The Astronomical Journal 135 991
A Bauer et al 2008 Nanotechnology 19 235202
Bifeng Pan et al 2009 Nanotechnology 20 125101
Michael Perkin et al 2008 Metrologia 45 07002
A H Harvey et al 2009 Metrologia 46 196
A Picard et al 2009 Metrologia 46 1
Yuchuan Cheng et al 2009 Nanotechnology 20 055604