Molecular beam epitaxy of InAs nanowires in SiO₂nanotube templates: challenges and prospects for integration of III–Vs on Si

Abstract

Guided growth of semiconductor nanowires in nanotube templates has been considered as a potential platform for reproducible integration of III-Vs on silicon or other mismatched substrates. Herein, we report on the challenges and prospects of molecular beam epitaxy of InAs nanowires in SiO 2 /Si nanotube templates. We show how and under which conditions the nanowire growth is initiated by In-assisted vapor-liquid-solid growth enabled by the local conditions inside the nanotube template. The conditions for high yield of vertical nanowires are investigated in terms of the nanotube depth, diameter and V/III flux ratios. We present a model that further substantiates our findings. This work opens new perspectives for monolithic integration of III-Vs on the silicon platform enabling new applications in the electronics, optoelectronics and energy harvesting arena.S Online supplementary data available from stacks.iop.org/NANO/27/455601/mmedia

Tuning growth direction of catalyst-free InAs(Sb) nanowires with indium droplets

“…The nano-bridges are particularly interesting since the second 'leg', which is formed after the second annealing step, grows in 〈111〉A direction. A-polar growth is very untypical for selfcatalyzed arsenide nanowires, and has only recently been observed in the case of InAs growing around Si/SiO 2 nanotubes [47]. Our results confirm that it is possible under certain conditions.…”

Fundamental aspects to localize self-catalyzed III-V nanowires on silicon

“…To gain access to this stage, we characterized the seeds below the gallium droplets, formed in the initial stage of growth after the gallium pre-deposition. We have recently shown that the incubation time required to start the nanowires can be as long as a few minutes 22 . We have also found that the distribution of the incubation times can be quite broad for low degrees of supersaturation in the vapor phase 22 .…”

“…We have recently shown that the incubation time required to start the nanowires can be as long as a few minutes 22 . We have also found that the distribution of the incubation times can be quite broad for low degrees of supersaturation in the vapor phase 22 . This broad distribution gives a more representative picture of possible initial configurations of the nanowire growth seeds.…”

Semiconductor nanowires: to grow or not to grow?

“…To give an example, silicon nanowires could be first etched on a substrate. These could be used as templates to initiate growth of III-V nanowires on their tips and create an axial heterostructure [52,275,276]. Likewise, etched III-V nanowire structures could benefit from passivation with a subsequent radial growth of a higher bandgap material.…”