Optical properties of Ga-doped AlN nanowires

We show that intentional Ga doping of AlN nanowires in the 0.01%-0.5% range leads to the spontaneous formation of nanometric carrier localization centers. Accordingly, for single nanowires, we observed a collection of sharp cathodoluminescence lines in a wavelength range spanning from 220 to 300 nm. From temperature-dependent cathodoluminescence, a ratio between the intensity at room temperature and 5 K of 20-30% is measured. We found that an ensemble of Ga-doped AlN nanowires exhibits a wide-band cathodoluminescence emission, which opens the path to the realization of efficient UV-C light emitting diodes covering a wide part of DNA absorption band.