Photoactivity and light harvesting in ZnO nanorod arrays/Au/CuS heterostructures

Abstract

Zinc oxide (ZnO) nanorod arrays (NRs)/gold (Au)/copper sulfide (CuS) heterostructures were grown by way of a low-temperature chemical approach, magnetron sputtering deposition and the successive ionic layer absorption and reaction route. The structural characteristics, morphological characteristics, elemental composition, current–voltage characteristics, ultraviolet–visible–near-infrared absorption and photocatalytic and photoelectrochemical properties of the ternary zinc oxide NR/gold/copper sulfide heterostructures were studied. The photocatalytic efficiency of the zinc oxide NRs/gold/copper sulfide heterostructures was higher than that of their zinc oxide NRs/copper sulfide counterparts. The zinc oxide NRs/gold/copper sulfide heterostructures were visible-light-photosensitive due to the lower bandgap of copper sulfide and localized surface plasmon resonance excitation of gold. The Schottky junction can motivate the photogenerated electron–hole to separate and transfer in opposite direction. The zinc oxide NRs/gold/copper sulfide heterostructures had a diode-like behavior. The electronic transition can be facilitated between ZnO NRs/gold/copper sulfide heterostructure and 1 M potassium hydroxide (KOH) electrolyte.