Fabrication, Structural, Electrical, and Optical Characterizations of p-Nanoparticle- and n-Nanotube-Based ZnO Homojunction

Abstract

Fabrication of zinc oxide (ZnO)-based p-n homojunction by depositing undoped p-ZnO nanoparticles (NPs) over electrodeposited n-ZnO hexagonal nanotube (NT) array is reported. Field emission scanning electron microscopy (FESEM) confirmed the formation of homojunction, while X-ray diffraction authenticated the crystallinity of the homojunction and its constituents. The conductivity type of the n- and p-type ZnO was ascertained by the Mott–Schottky plot obtained from electrochemical impedance spectroscopy (EIS) measurements. The fabricated p-n homojunction showed green luminescence emission (not shown in the case of only p- or n-ZnO) in the visible range, which was confirmed by the photoluminescence (PL) study. Au/p-ZnO NPs/n-ZnO NTs/Au offered a cut-in voltage of 0.45–0.33 V and a breakdown voltage of ~−2.68 V in the temperature range of 25–75 °C, as revealed from the I – V and C – V measurements