  Structural analysis of self-catalyzed GaAs nanowires (NWs) grown on
lithography-free oxide patterns is described with insight on their growth
kinetics. Statistical analysis of templates and NWs in different phases of the
growth reveals extremely high dimensional uniformity due to a combination of
uniform nucleation sites, lack of secondary nucleation of NWs, and
self-regulated growth under the effect of nucleation antibunching.
Consequently, we observed the first evidence of sub-Poissonian GaAs NW length
distributions. The high phase purity of the NWs is demonstrated using
complementary transmission electron microscopy (TEM) and high-resolution x-ray
diffractometry (HR-XRD). It is also shown that, while NWs are to large extent
defect-free with up to 2 um long twin-free zincblende segments, low temperature
micro-photoluminescence spectroscopy reveals that the proportion of
structurally disordered sections can be detected from their spectral
properties.
