Existing barriers to efficient deep
ultraviolet (UV)
light-emitting
diodes (LEDs) may be reduced or overcome by moving away from conventional
planar growth and toward three-dimensional nanostructuring. Nanorods
have the potential for enhanced doping, reduced dislocation densities,
improved light extraction efficiency, and quantum wells free from
the quantum-confined Stark effect. Here, we demonstrate a hybrid top-down/bottom-up
approach to creating highly uniform AlGaN core–shell nanorods
on sapphire repeatable on wafer scales. Our GaN-free design avoids
self-absorption of the quantum well emission while preserving electrical
functionality. The effective junctions formed by doping of both the
n-type cores and p-type caps were studied using nanoprobing experiments,
where we find low turn-on voltages, strongly rectifying behaviors
and significant electron-beam-induced currents. Time-resolved cathodoluminescence
measurements find short carrier liftetimes consistent with reduced
polarization fields. Our results show nanostructuring to be a promising
route to deep-UV-emitting LEDs, achievable using commercially compatible
methods.