Optics & Laser Technology 157 (2023) 108776 Available online 17 October 2022 0030-3992/© 2022 Elsevier Ltd. All rights reserved. Full length article High-responsivity self-powered UV photodetector performance of pristine and V-doped ZnO nano-fowers Mohan Reddy Pallavolu a , Reddeppa Maddaka b , Sujaya Kumar Viswanath c , Arghya Narayan Banerjee a, * , Moon-Deock Kim d , Sang Woo Joo a, * a School of Mechanical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea b Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, MI, 48109, USA c School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore d Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea A R T I C L E INFO Keywords: ZnO nano-fowers Co-precipitation method Self-assembly growth V-doping Self-powdered UV-photodetectors High responsivity ABSTRACT Wurtzite ZnO nanostructures are suitable for high-performance, self-powered photodetectors (PDs) because of their attractive optoelectronic properties. In this study, highly sensitive ultra-violet self-powered PDs with high responsivity/detectivity and large external quantum effciency was developed by V-doped ZnO nanofower samples onto an ITO glass substrate. Highly faceted pristine and V-doped ZnO nanofowers were produced using a simple, low-cost co-precipitation method. The presence of Na + ions in the precursor solution appeared to control the morphology of the nanomaterial. Various physicochemical characterizations showed that the vari- ation of the Na + ion concentration inhibits the reaction at selected regions, causing the branching of nano- structures to form ZnO nanofowers. Room- and low-temperature photoluminescence studies showed that V- doping increases the extrinsic carrier density and produces many intrinsic and extrinsic defect states, which reduce the e  –h + recombination rate signifcantly and produce a large photocurrent under UV illumination. The V-ZnO-based self-powered UV PD device showed a 156 % increase in photocurrent compared to pristine ZnO- based PDs, with very short response/recovery times of 0.22/0.23 s under 382 nm UV illumination of 1.14 mW/cm 2 , and excellent responsivity (5.1 × 10 3 mA/W), very high external quantum effciency (5.5 × 10 4 %), and large detectivity (4.0 × 10 13 Jones). Therefore, the current work presents a simple way to obtain high- performance self-powered UV PDs that can open up a new horizon to fabricate new-generation optoelectronic devices for diverse applications. 1. Introduction Photodetectors (PDs) are used in various applications, including optical imaging, optoelectronic circuits, military surveillance, space communication, air quality monitoring, fame monitoring, and indus- trial quality control [1–4]. Because metal–oxidesemiconductor mate- rials have a wide range of spectral applications, their optical properties (bandgap) must be tuned. As a result, they are typically doped with metals [5] or non-metals [6], joined with other metals/functional groups and designed as a composite material with other semiconductor materials [7,8]. To accomplish visible-light detection response, most of these procedures used for changing the optical characteristics necessi- tate complex, expensive equipment, and a complex device structure. In terms of metal–oxide semiconducting materials, zinc oxide (ZnO) is a well-researched and effective material for PD applications because of its relative temperature and chemical durability, good oxidation resistance, and excellent biocompatibility, low cost, non-toxicity, and high con- ductivity. ZnO has n-type semiconducting properties with large bandgap of 3.37 eV, corresponding to UV light. ZnO nanostructures are ultimate for a variety of applications, including food processing, sterilizing, medical equipment, research labs, and semiconductors manufacturing, where the installation of UV detectors is crucial. These applications are made possible by the excellent physicochemical properties of ZnO nanostructures, including large surface area, radiation hardness [9], superior spatial resolution [10], and high electron mobility. Addition- ally, light emitting diodes (LEDs), surface acoustic waves, solar cells, thin-flm transistors and energy harvesting devices are further applica- tions for ZnO that are in high demand [11]. * Corresponding authors. E-mail addresses: arghya@ynu.ac.kr (A.N. Banerjee), swjoo@yu.ac.kr (S.W. Joo). Contents lists available at ScienceDirect Optics and Laser Technology journal homepage: www.elsevier.com/locate/optlastec https://doi.org/10.1016/j.optlastec.2022.108776 Received 1 August 2022; Received in revised form 19 September 2022; Accepted 5 October 2022