Conductive atomic force microscopy has been used to characterize single GaN nanorod Schottky and p-n junction diodes. The ideality factor, reverse breakdown voltage, and the Schottky barrier height of individual nanorod diodes were compared to those from conventional thin-film diodes. Large-area contacts, enabling diodes with arrays of GaN nanorods in parallel, were also fabricated and their electrical characteristics investigated. The defect-free nature of the GaN nanorods and enhanced tunneling effects due to nanoscale contacts have been invoked to explain the electrical behavior of the nanorod diodes.

Monocrystalline, vertically aligned and faceted GaN nanorods with controlled diameter have been synthesized by selective organometallic vapor phase epitaxy (OMVPE) onto GaN exposed at the bottom of pores in silicon dioxide templates patterned by reactive ion etching through self-organized porous anodic alumina films. This process is free of foreign catalysts, and the nanorod diameter control is achieved without the need for low-throughput nanolithographic techniques. The use of conventional OMVPE growth conditions allows for the straightforward adaptation of conventional doping and heterostructure growth as will be necessary for the fabrication of nanorod-based strain-relaxed electrically pumped lasers and light-emitting diodes.

Increasing the luminance of white LEDs to the 200 Mnit level and beyond, opens a completely new design space for a wide range of lighting applications, by allowing significant reductions in optics and luminaire size as well as costs. Moreover, new applications, such as dynamic beam steering, are enabled by the ability to create arrays of densely packed, individually addressable high‐luminance emitters. The development of such high‐luminance LEDs requires improvements in all LED technology elements. In this paper, we discuss recent advances in epitaxy, die, phosphor, and package technology that are critical to achieving these benefits.

Vacuum field emission from GaN and (Al,Ga)N∕GaN nanorods with pyramidal tips has been measured. The turn-on fields, defined at a current density of 0.1μA∕cm2, were found to be 38.7 and 19.3V∕μm, for unintentionally doped GaN and (Al,Ga)N∕GaN nanorods, respectively. The 5nm (Al,Ga)N layer reduced the electron affinity at the surface, thereby lowering the turn-on field and increasing the current density. The nanostructures exhibit a field enhancement factor of approximately 65 and the work function of the (Al,Ga)N∕GaN nanorod heterostructure was estimated to be 2.1eV. The stability of the emission characteristics and the simple fabrication method suggest that intentionally doped and optimized (Al,Ga)N∕GaN nanorod heterostructures may prove suitable for field-emission device.