Cr-Doping-Induced Fano Resonance of ZnO-Layered Nanoporous Structures and UV Photodetector Application

Abstract

In this study, a layered nanoporous structure of Cr-doped zinc oxide (ZnO) was synthesized by a simple hydrothermal and post-annealing technique. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet (UV)−visible spectroscopy techniques. The XRD peak shift provides additional evidence of the incorporation of the dopant. Field emission scanning electron microscopy was used to confirm the porous morphology. From high-resolution transmission electron microscopy pictures, the pore size and crystallographic layouts were calculated. UV−vis spectra demonstrated that the absorbance improved, and a reduction in band gap was observed with an increment in dopant concentration. The vibrational modes of the produced ZnO sample were analyzed by Raman spectroscopy, which confirmed the absence of other contaminants. Upon addition of the dopant, the phonon peaks showed asymmetric broadening caused by the interaction of discrete states with continuum states. Due to the strong contact, the asymmetry got worse as the dopant concentration increased. Finally, current−voltage (I−V) measurements indicated a great enhancement after Cr doping in UV photoresponse. The UV light detection phenomenon can be ascribed to the trapping and detrapping of electrons by Cr-related defects.

Self-Powered Quasi-Solid-State Photoelectrochemical Photodetectors Based on MXene Paper Modified by ZnO Nanostructured Architecture

“…Unfortunately, most of the literature reports have agreed that pristine ZnO-based PDs exhibit slow response time because of the atmospheric adsorbates such as oxygen and water molecules, creating charge trap states on the surface . Therefore, a great effort has been devoted to improving the optoelectronic and photodetection properties of ZnO. − The most common routes to enhance the photoresponse performance of ZnO-based PDs are doping of metals and preparing nanocomposites. − In our previous research, flexible pristine and Mn-doped ZnO NRs (Mn/ZnO NR)-deposited MSM-type PDs were thoroughly investigated in terms of photoresponse time and detectivity . We observed that the photodetection parameters such as detectivity ( D *), responsivity ( R ), and response/recovery time have been improved by the Mn dopant.…”