III-Nitride quantum dots in nanowires: growth, structural, and optical properties

Nanowires (NWs) have emerged as a platform to build complex, self-assembled, defect-free nanostructures. In particular, the growth of single islands/disks of various III-nitride combinations (InGaN in GaN, GaN in AlN, AlGaN in AlN) are possible in NW heterostructures, extending the field of experimental quantum dot exploration. Specific to NWs, the possibility to disperse them paves the way to probe and investigate only a single wire/dot. In the present article, the growth of GaN disks/islands and InGaN islands as well as their optical properties at the nanometer scale will be reviewed. Besides the intentional growth of QD-in NW heterostructures, special attention will be paid to compositional fluctuations in ternary alloy nanowires, which also lead to a quantum dot-like behavior. Specific to NW geometry, optical emission is expected to exhibit a high degree of polarization along the NW axis, opening a pathway to the practical realization of polarized single photon emitters in a wide range of wavelengths.