EPR and DRS evidence for NO2 sensing in Al-doped ZnO

TitleEPR and DRS evidence for NO2 sensing in Al-doped ZnO
Publication TypeJournal Article
Year of Publication2008
AuthorsNavale, SC, Ravi, V, Srinivas, D, Mulla, IS, Gosavi, SW, Kulkarni, SK
JournalSensors and Actuators B-Chemical
Volume130
Issue2
Pagination668-673
Date PublishedMAR
Type of ArticleArticle
ISSN0925-4005
Keywordsaluminum doping, DRS, EPR, NO2 sensor, ZnO
Abstract

Zinc oxide (ZnO) is a well-known semiconducting multifunctional material wherein properties right from the morphology to gas sensitivity can be tailor-made by doping or surface modification. Aluminum (Al)-incorporated porous zinc oxide (AI:ZnO) exhibits good response towards NO2 at low-operating temperature. The NO2 gas concentration as low as 20 ppm exhibits S = 17% for 5 wt. % Al-incorporated ZnO. The NO2 response increases with operating temperature and concentration and reaches to its maximum at 300 degrees C without any interference from other gases such as SO3, HCl, LPG and alcohol. Physico-chemical characterization likes differential thermogravimetric analysis (TG-DTA) electron paramagnetic resonance (EPR) and diffused reflectance spectroscopy (DRS) have been used to understand the sensing behavior for pure and A]-incorporated ZnO. The TG-DTA depicts formation of ZnO phase at 287 degrees C. The EPR study reveals distinct variation for O- (g=2.003) and Zn interstitial (g = 1.98) defect sites in pure and Al:ZnO. The DRS studies elucidate signature of adsorbed NO, species in aluminium-incorporated zinc oxide indicating its tendency to adsorb these species even at low temperatures. This paper is an attempt to correlate the gas sensing behavior with the physico-chemical studies such as EPR and DRS. (c) 2007 Published by Elsevier B.V.

DOI10.1016/j.snb.2007.10.055
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)4.758
Divison category: 
Physical and Materials Chemistry