Open AccessSensing Performance of a ZnO-based Ammonia Sensor
Author(s) -
Dinesh Kumar Chaudhary,
Yogesh Singh Maharjan,
Sanju Shrestha,
Surendra Maharjan,
Shankar Prasad Shrestha,
Leela Joshi
Publication year - 2022
Publication title -
journal of physical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.244
H-Index - 20
eISSN - 1675-3402
pISSN - 2180-4230
DOI - 10.21315/jps202.33.1.7
Subject(s) - wurtzite crystal structure , materials science , crystallite , scanning electron microscope , band gap , water vapor , thermal stability , oxide , optoelectronics , ammonia , analytical chemistry (journal) , zinc , nanotechnology , chemical engineering , environmental chemistry , composite material , chemistry , metallurgy , organic chemistry , engineering
Monitoring and remediation of toxic and flammable gases have become a critical task for the development of a clean society. Among various types of metal oxide semiconductors (MOS), zinc oxide (ZnO) is considered a potential material for gas sensing application because of its high sensitivity, easy synthesis, and high thermal stability behaviours. This research aimed to gain an in-depth understanding of the sensing task of a very stable and porous thin film of spin coated ZnO for detecting toxic ammonia vapour at room temperature. As-prepared ZnO films were characterised by x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) analyses. XRD and SEM results revealed the polycrystalline wurtzite ZnO phase with grainy surface morphology. Optical calculations quantify the direct band gap of ZnO as 3.2 eV. The sensitivity measurements showed a good response ratio of 38.5 ± 0.6 with an exposure of 400 ppm of ammonia vapour. The results on sensitivity measurement of several cycles illustrated its stability and sensing performance better than other reported similar works. These findings will be useful to develop a low cost and efficient room temperature MOS gas sensor that can efficiently detect extremely low concentrations as 20 ppm of ammonia vapour which is below the Occupational Safety and Health Administration (OSHA) recommended value.