Assessment of waveguiding properties of gallium oxide nanostructures by angle resolved cathodoluminescence in a scanning electron microscope

► Waveguiding behaviour of gallium oxide nanowires is studied using angle resolved CL. ► Quantitative analysis of optical losses in sub-wavelength nanowires is carried out. ► There is a strong dependence of the optical losses on the substrate. ► Directional-dependant light guiding is observed in branched planar microstructures.