Figure 3

SEM image of the patterned area with GaN planar nanowires with width of 6 µm (a) and 2 µm (b). The enlarged image of thinner planar stripes is depicted as the inset. (c) Low-temperature CL spectra taken from average patterned area (a) and (b) are shown by green and blue lines, respectively. Emission spectrum shown by the red line is measured for a single stripe, i.e. when the electron beam is in the focused mode. CL spectrum measured for the bare epitaxial GaN layer is shown by a black line. Spectra are normalized and shifted vertically for clarity.