The effect of rare-earth element (Gd, Nd, La) doping of NiO films on UV photodetector

Haunsbhavi, K and Kumar, KDA and Ubaidullah, M and Shaikh, SF and Venkatesh, R and Alagarasan, D and Murahari, P and Angadi, B (2022) The effect of rare-earth element (Gd, Nd, La) doping of NiO films on UV photodetector. In: Physica Scripta, 97 (5).

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Abstract

The semiconductor-based UV photodetectors are the most essential devices in the field of space observations, military, DNA sequencing, analysis of protein, medical imaging, checking of atmospheric pollution, optical communications radiation, etc. With such a wide range of possible applications, the nanostructured pristine and rare-earth (RE) doped NiO ((NiO: Gd(1), NiO:Nd(1), NiO:La(1)) thin films were prepared and investigated for their suitability as UV photodetectors. The films were prepared by nebulized spray pyrolysis (NSP) at a substrate temperature of 450 °C. The x-ray diffraction studies confirm the cubic single phase with the polycrystalline nature of the prepared films. The spectroscopic studies such as absorbance and photoluminescence confirm that increase in the optical bandgap and 391 nm PL emission is attributed to the near band edge emission of the NiO. The x-ray photoelectron spectroscopy reveals the presence of nickel and the doped elements with their oxidation states. The UV photodetector performance of the prepared NiO films was carried out under the irradiation of 365 nm light. The NiO:Gd exhibits the best responsivity (0.353 AW-1), external quantum efficiency (120), detectivity (1.72 � 1010 Jones) and rise time (2.0 s), and fall time (2.2 s). Importantly, strategies such as limited doping (1 at.) and larger ionic radii of Gd incorporation into the host NiO cause a moderate increase in the lattice distortion and inhibit the recombination rate instead of behaving as a recombination center. In addition, the conduction band (CB) electrons are trapped by a greater number of oxygen vacancies residing at the Gd3+ 4f state and cause a good separation of charge carriers. Overall, these modifications enhance the mean lifetime of electrons, consequently reducing the recombination rate and enhancing the photoresponse. © 2022 IOP Publishing Ltd.

Item Type:	Journal Article
Publication:	Physica Scripta
Publisher:	IoP Publishing
Additional Information:	The copyright for this article belongs to IoP Publishing.
Keywords:	DNA sequences; Energy gap; Film preparation; Medical imaging; Military applications; Nanocrystals; Nickel oxide; Photodetectors; Rare earths; Samarium compounds; Semiconductor devices; Semiconductor doping; Spectroscopic analysis; Spray pyrolysis; Thin films; X ray photoelectron spectroscopy, La doping; Lattice distortions; Nebulisers; Nebulizer spray pyrolyse; NiO films; NiO thin film; Optical-bandgap; Rare earth ions; Recombination rate; UV photodetectors, Photons
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 May 2022 14:38
Last Modified:	22 May 2022 14:38
URI:	https://eprints.iisc.ac.in/id/eprint/72455

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