Fabrication and electrical properties of axial and radial GaAs nanowire pn junction diode arrays

We report on the fabrications and characterizations of axial and radial GaAs nanowire pn junction diode arrays. The nanowires are grown on n-doped GaAs (111)B substrates using the Au-catalyzed vapor–liquid–solid mechanism by metal–organic chemical vapor deposition (MOCVD). Diethyl–zinc and silane are used as p- and n-type dopant precursors, respectively. Both the axial and radial diodes exhibit diode-like J–V characteristics and have similar performances under forward bias. Under backward bias, the axial diode has a large leakage current, which is attributed to the bending of the pn junction interface induced by two doping mechanisms in Au-catalyzed nanowires. The low leakage current and high rectification ratio make the radial diode more promising in electrical and optoelectronic devices.