High-Responsivity and Dual-Band ZnO UV Photodetectors via Additive-Engineered Nanowalls and Nanorods

Abstract

A facile additive-assisted hydrothermal route is demonstrated to realize high-performance ZnO ultraviolet (UV) photodetectors. Incorporation of trisodium citrate and potassium dichromate into the growth solution enables selective formation of ZnO nanowalls and nanorods. X-ray photoelectron spectroscopy confirms Cr3+ incorporation and associated defect-state modulation in the ZnO lattice. The nanowall device exhibits high responsivity (~1.4 × 103 A/W), photosensitivity (~3.7 × 106), and detectivity (~1.3 × 101s Jones), attributed to efficient lateral charge transport and reduced carrier trapping, whereas nanorods display a distinct dual-band photoresponse near ~330 and ~370 nm due to additive-induced sub-bandgap states. This simple, low-temperature, and cost-effective approach provides a scalable route for tailoring ZnO nanostructures for high-sensitivity and dual UVA-band photodetection, enabling applications in environmental monitoring, flame detection, secure optical communication, and wearable health diagnostics. © 1989-2012 IEEE.