Effects of the formation temperature of Au + Ga solid-solution droplets on the growth behaviors of GaN nanowires on Si(111) by using MOCVD

Gallium nitride (GaN) nanowire (NW) arrays were grown on gold-coated Si(111) substrates by using metal-organic chemical vapor deposition (MOCVD). The size of the Au + Ga solid-solution droplets was considered to be an important parameter of GaN NW growth. In this study, the GaN NWs were grown using Au + Ga solid-solution droplets of various sizes about 100, 200, and 300 nm under identical growth conditions. Field emission scanning electron microscopy (F.-SEM) images demonstrate the effect of droplet size on the growth of GaN NWs. The transmission electron microscopy (TEM) images and the selected area electron diffraction (SAED) patterns demonstrate that the grown GaN NWs are crystalline with a single-crystal wurtzite structure. The photoluminescence and the cathodoluminescence spectra reveal a sharp peak at 366 nm with a full width at half maximum (FWHM) of 89 meV and at 3.36 eV with an FWHM of 76 meV, respectively, clearly indicating that the grown GaN NWs are highly crystalline in nature.