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

Cathodoluminescence (CL) of Ga₂O₃ nanowires and planar microstructures has been studied in a scanning electron microscope, as a function of the orientation angle of the structures relative to the position of the light detection system in the microscope chamber. CL contrast shows a marked dependence on the detection angle due to the waveguiding behaviour of the structures. The angle resolved cathodoluminescence (ARCL) measurements enable to evaluate the optical losses of guided blue-ultraviolet light in nanowires with diameters in the sub-wavelength range, deposited on graphite tape or silicon. In planar, branched feather-like microstructures, ARCL images demonstrate the directional-dependant light guiding behaviour of the nano-branches.