Studies on pure and Zn doped NiO nanostructured thin films for enhanced ammonia gas sensing applications

Abstract

Thin films of pure NiO and doped with Zn are prepared by varying dopant concentration using spray pyrolysis. This paper presents the characteristics of thin films, including their structure, morphology, chemical composition, optical properties, and gas-sensing abilities. By adding 2 wt% Zn to pure NiO matrix, the film's structural, morphological, and ability to sense ammonia gas were notably changed. The Zn-doped NiO thin films were effective ammonia gas sensors with reliable performance at room temperature, making them suitable for real-time detection and monitoring of ammonia vapours. Gas-sensing studies suggest that the Zn-doped NiO thin film gas sensor can simultaneously improve stability, reproducibility, and sensitivity. Additionally, the NiO thin film of the p-type has a higher binding affinity for NH3 gas than other test gases. The 2 wt% Zn-doped NiO thin film exhibited an excellent response of 53.2 with response and recovery times of 24 and 30 s towards 25 ppm of NH3 at room temperature.