Ultrasensitive nitric oxide gas sensors based on Ti-doped ZnO nanofilms prepared by RF magnetron sputtering system

It is aimed to explore the advantages of titanium doping and magnetron sputtering as opposed to chemicalbased methods on the surficial and electrical characteristics of ZnO films and their gas sensing performance in particular. RF magnetron sputtering was employed to synthesize a pure ZnO nanofilm as a reference and Ti-doped ZnO nanofilms with various Ti contents. The doping process was done by sputtering Ti-doped ZnO targets developed through solid-state reaction, and doping content was determined by EDS analysis. All nanofilms exhibited pure hexagonal wurtzite structure and relatively flat and homogenous surfaces with a clear distribution of nanoparticles in the Ti-doped samples. The observed enhancement in the properties of the nanofilms was reflected in the ultimate performance of the gas sensor. In this regard, the sensor with 1 wt% Ti content showed the best gas sensing performance with an ultra-sensitivity of 1.72 for 1 ppm and 0.9 for 1 ppb NO gas at a relatively low working temperature of 167 degrees C. The sensor also acquired outstanding stability, quick responsivity, reproducibility and superior selectivity required for NO monitoring. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

This study aims to explore the advantages of titanium doping and magnetron sputtering over chemical-based methods on the surficial and electrical characteristics of ZnO films, specifically on their gas sensing performance. Pure ZnO nanofilm and Ti-doped ZnO nanofilms with different Ti contents were synthesized using RF magnetron sputtering. The nanofilms exhibited a pure hexagonal wurtzite structure, with relatively flat and homogenous surfaces and a clear distribution of nanoparticles in the Ti-doped samples. The enhanced properties of the nanofilms were reflected in the gas sensor's ultimate performance, with the 1 wt% Ti content sensor showing the best gas sensing performance.