Localized cathodoluminescence investigation on single Ga2O3 nanoribbon/nanowire

The cathodoluminescence (CL) upon electron excitation of the Ga2O3 nanoribbons and nanowires was characterized using a hybrid set-up based on combination of a scanning probe microscope (SPM) and a field emission scanning electron microscope (FE-SEM). An optical fiber was mounted in the system in such a way that it can be controlled to approach closely a selected nanostructure of interest so as to collect the local CL signal directly arising from it. The thicker nanoribbons (thickness >170 nm) show an emission peak around 410 nm, while the thinner ribbons/nanowires, smaller than 40 nm in thickness/diameter, have a shifted emission around 490 nm. The observed shift in the CL peaks is attributed to the difference of the oxygen vacancies in the nanostructures. Our results demonstrate that the localized CL spectroscopy is a powerful means of selective addressing the optical properties of the semiconductor nanostructures.