Structural Investigation of Uniform Ensembles of Self-Catalyzed GaAs Nanowires Fabricated by a Lithography-Free Technique.
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 a large extent defect-free with up to 2-μm-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.
Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu 3, FI-33720, Tampere, Finland. eero.koivusalo@tut.fi.
Eero
http://orcid.org/0000-0001-5029-4658
E
Koivusalo
Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu 3, FI-33720, Tampere, Finland.
Teemu
T
Hakkarainen
Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu 3, FI-33720, Tampere, Finland.
Mircea
M
Guina
GaAs; Microstructure; Molecular beam epitaxy; Nanowires