Enhanced ammonia sensing of ZnO thin films through Yttrium doping by cost-effective nebulizer spray pyrolysis method. (28th September 2021)

• Record Type: Journal Article
• Authors: Ravichandran, K; Santhosam, A Jansi; Aldossary, Omar M; Ubaidullah, Mohd
• Is Part Of: Physica scripta. Volume 96:Number 12(2021)
• Publication Date: 2021-09-28
• Subjects: thin films -- yttrium doped ZnO -- nebulizer spray pyrolysis -- NH3 sensor; Physics -- Periodicals; 530.05
• DOI: 10.1088/1402-4896/ac2545
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Yttrium (Y) doped (doping concentration-0, 1, 3 and 5 wt%) ZnO thin films were deposited using spray pyrolysis technique. Structural, surface morphological, optical and compositional properties were analyzed using x-ray diffraction (XRD), Atomic Force Microscopy (AFM), UV–vis NIR spectrophotometry (UV), photoluminescence studies (PL) and elemental composition analysis. Ammonia vapour sensing properties such as response/recovery, stability and repeatability were studied at room temperature. XRD results confirmed that the prepared samples have hexagonal wurtzite structure. ZnO:Y thin film with 5 wt% yttrium doping exhibits excellent sensing response of 99, fast response/recovery times of 29 s/7 s which may be due to the existence of oxygen vacancies in ZnO:Y (5 wt%) film sample as confirmed by photoluminescence (PL) study. These oxygen vacancies attract more electrons and thus enhance the gas sensing. In addition, increase in number of active sites caused by substitution of Y 3+ (trivalent) ions into Zn 2+ (divalent) regular sites as confirmed by the observed M-B (Moss-Burstein) effect, also causes an enhancement in the gas sensing. Surface roughness, another reason for the enhanced sensitivity has been confirmed by AFM.