Fabrication of Er, Tb doped CuO thin films using nebulizer spray pyrolysis technique for photosensing applications

Abstract

CuO-based high-performance photo-sensors are a key area of research and challenge in today's scenario. In view of this, we study undoped, CuO:Er (1%),CuO:Tb (1%), and Er(1%),Tb(1%) dual doped CuO thin films for photodetector applications using the nebulizer spray pyrolysis technique. The structural, morphological, and optical features of the coated samples were systematically studied using few techniques such as X-ray diffraction (XRD), Scanning electron microscope (SEM), UV–Vis spectra, Photoluminescence (PL) and two probes. According to the XRD analysis, all the doped thin films show a good crystalline structure with a predominant peak exhibition (002) plane and the doping process enlarged the crystallite size value and obtained a maximum of 44 nm for Er,Tb dual doped CuO film. SEM photo shows the formation of a flaky nanoparticle structure. In the case of light absorption, the absorption level depends on dopant materials such as Er and Tb and the UV absorption level is improved for the dual doped film. The photo-luminescence shows that all the prepared samples exhibit defect-related peaks around 412, 450, 475, 525 nm and the doping process significantly improves the luminescence properties of CuO films. According to Hall effect analysis all prepared samples show the p-type characteristics whose film resistance and mobility are increased and the highest value is noted for Er(1%),Tb(1%) doped CuO thin film. The photo-detection capacity was studied by the analysis of optoelectronic properties for these doped CuO thin films. The UV sensing study indicates, high responsivity (4.85⨯10−1AW−1), external quantum efficiency (113%), and detectivity (1.89⨯1010 Jones) values for the Er, Tb dual doped CuO photodetector. The work also discusses a possible mechanism of ultraviolet photo-detector performance. These findings share a guideline to develop a high-performance photodetector.