The synthesis and electrical characterization ofCu2O/Al:ZnO radial p–n junction nanowire arrays

Abstract

Vertically aligned large-area p-Cu2O/n-AZO (Al-doped ZnO) radial heterojunction nanowire arrays were synthesized onsilicon without using catalysts in thermal chemical vapor deposition followedby e-beam evaporation. Scanning electron microscopy and high-resolutiontransmission electron microscopy results show that poly-crystallineCu2O nano-shells with thicknesses around 10 nm conformably formed on the entire periphery ofpre-grown Al:ZnO single-crystalline nanowires. The Al doping concentration in the Al:ZnOnanowires with diameters around 50 nm were determined to be around 1.19 at.% by electronenergy loss spectroscopy. Room-temperature photoluminescence spectra show that thebroad green bands of pristine ZnO nanowires were eliminated by capping withCu2O nano-shells. Thecurrent–voltage (I–V) measurementsshow that the p-Cu2O/n-AZO nanodiodes have well-defined current rectifying behavior. This paper provides asimple method to fabricate superior p–n radial nanowire arrays for developing nano-pixeloptoelectronic devices and solar cells.