Highly sensitive ultraviolet photodetectors fabricated from rare earth metal ions doped NiO thin films via nebulizer spray pyrolysis method

In this report, an automated nebulizer spray pyrolysis (NSP) route was chosen to prepare pure NiO and (1%-Er, Tb, Pr) RE doped NiO thin films samples on glass slides at 450 degrees C using nickel chloride as a source. Through systematical investigation their microstructure (XRD), surface morphology (FESEM), composition (EDX), optical (UV-Vis absorption and photoluminescence), UV photoconduction (Keithly source meter 2450) information were obtained. The face centered cubic structure occupying the space group (Fm3m) of NiO thin films was confirmed without any impurity phase through X-ray diffraction (XRD) analysis. Also, the effect of (1%-Er, Tb, Pr) RE doping with NiO on the crystallite size confirms that the higher ionic radii Pr doped NiO sample possess a higher crystalline size of 31 nm. The morphological studies show that the pure and RE doped with NiO thin film samples possess highly dense cloudy spherical morphology. UV studies show that the Pr doped NiO sample exhibits higher absorption and lower bandgap of 3.49 eV. The emission peaks related to the presence of defect sites were studied through the PL analysis showing higher recombination centers occur for the Pr-doped NiO sample suggesting the sample possesses a higher carrier concentration. The fabricated pure and (1%-Er, Tb, Pr) RE doped NiO thin film photodetectors were analyzed through I-V, photo sensing parameters, and transient characteristics. The results show that the Pr-doped NiO photodetector sample possesses higher photocurrent, better responsivity (3.45 x10(-1) AW(-1)), detectivity (1.20 x10(10) Jones), EQE (81%), and the photo transient characteristics shows better response and repeatability of the photodetector samples under varying UV light intensities (1-5 mW/cm(2)). From the photo sensing results, it is confirmed that the Pr doped NiO photodetector sample can be better suited for the application of photodetectors. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

An automated nebulizer spray pyrolysis (NSP) route was used to prepare pure NiO and (1%-Er, Tb, Pr) RE doped NiO thin films on glass slides. The microstructure, surface morphology, composition, optical properties, and UV photoconduction of the samples were systematically studied. The Pr-doped NiO sample showed better performance in terms of photocurrent, responsivity, detectivity, and EQE, making it suitable for photodetector applications.