The role of silver doping in tuning the optical absorption, energy gap, photoluminescence properties of NiO thin films for UV photosensor applications

Abstract

NiO thin films were grown systematically using the nebulizer spray pyrolysis (NSP) method with different additions of Ag 1%, 2%, and 3% respectively. A photodetector was fabricated using NiO:Ag thin films. The structural, morphological, compositional, optical, and electrical properties of NiO:Ag thin films were studied as a function of Ag addition. XRD studies show a gradual reduction in the intensity and the broadening with Ag addition, which confirms the formation of nanoparticles. Ag phase has been formed after 3% of Ag addition. Compositional studies using EDS confirms the presence of all the elements. The energy band gap of films is found to be in the range 3.25–3.45 eV with an Ag addition of 1–3%. I–V characteristics and photoresponse of photodetectors were recorded under UV light illumination. The parameters of a photodetector such as external quantum efficiency, responsivity and detectivity were calculated. The observed photo responsivity increases with an increase of Ag (1%) and decreases further higher Ag concentrations.The maximum responsivity is observed for the NiO film with 1%Ag. The photoresponse of all samples confirmed the stable and reproducible characteristics such as external quantum efficiency, responsivity and detectivity.The enhanced properties observed for 1% of Ag-doped film may find applications in the fabrication of optoelectronic devices.