Improving Photoresponsivity of ZnO Nanorods Film by a Combination Doping with Nickel and Adding Cu<sub>2</sub>O Layer

Abstract

ZnO Nanorods (NRs) is an excellent material for optoelectronic applications. However, ZnO NRs have a wide bandgap. To overcome this problem, ZnO Nanorods has been doped with nickel (0, 3, and 7 at.%) and then coated by a Cu2O layer. The ZnO nanorods were first prepared using a hydrothermal method where nickel of varying concentration was added as a dopant. The prepared samples were then coated by Cu2O using a Chemical Bath Deposition (CBD) method. The fabricated composites were characterized by XRD to identify the phase compositions, SEM-EDX to determine the morphology and elemental compositions, UV-Vis spectroscopy to determine the bandgap, and photocurrent response test to study the sample's response to light. The XRD reveals that the pristine ZnO and Ni-doped ZnO have the same diffraction patterns but the peaks shift to the right with increasing dopant concentrations. The SEM images of all samples show ZnO NRs grew perpendicular to the substrate while its EDX spectra confirm the presence of Nickel in the Ni-doped samples. The UV-Vis spectra showed that the calculated bandgap decreases from ~ 3.2 to 2.7 eV by increasing nickel dopant concentration and adding Cu2O layer. The photocurrent response measurement shows that the ITO/Zn0.93Ni0.07O/Cu2O sample had a good response to light compared to the two other samples.