Open AccessBroadband Dielectric Spectroscopic Detection of Volatile Organic Compounds with ZnO Nanorod Gas Sensors
Author(s) -
Papa K. Amoah,
Pengtao Lin,
Helmut Baumgart,
Rhonda Franklin,
Yaw S. Obeng
Publication year - 2020
Publication title -
journal of physics. d, applied physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.857
H-Index - 198
eISSN - 1361-6463
pISSN - 0022-3727
DOI - 10.1088/1361-6463/abd3ce
Subject(s) - broadband , materials science , dielectric , nanorod , electrical resistivity and conductivity , optoelectronics , metrology , zinc , semiconductor , nanotechnology , analytical chemistry (journal) , optics , chemistry , electrical engineering , environmental chemistry , physics , engineering , metallurgy
Metal-oxide (MO) semiconductor gas sensors based on chemical resistivity necessarily involve making electrical contacts to the sensing materials. These contacts are imperfect and introduce errors into the measurements. In this paper, we demonstrate the feasibility of using contactless broadband dielectric spectroscopy (BDS)-based metrology in gas monitoring that avoids distortions in the reported resistivity values due to probe use, and parasitic errors (i.e. tool-measurand interactions). Specifically, we show how radio frequency propagation characteristics can be applied to study discrete processes on MO sensing material, such as zinc oxide (i.e. ZnO) surfaces, when exposed to a redox-active gas. Specifically, we have used BDS to investigate the initial oxidization of ZnO gas sensing material in air at temperatures below 200 °C, and to show that the technique affords new mechanistic insights that are inaccessible with the traditional resistance-based measurements.