Investigation of structural characteristics of III-V semiconductor nanowires grown by molecular beam epitaxy

In this study, the structure and quality controlled growth of InAs nanowires using Au catalysts in a molecular beam epitaxy reactor is present. By tuning the indium concentration in the catalyst, defect-free wurtzite structured and defect-free zincblende structured InAs nanowires can be induced. It is found that these defect-free zinc-blende structured InAs nanowires grow along < ̅ ̅0> directions with four lowenergy {111} and two {110} side-wall facets and adopt the ( ̅ ̅ ̅) catalyst/nanowire interface. Our structural and chemical characterizations and calculations identify the existence of catalyst supersaturation threshold for the InAs nanowire growth. When the In concentration in the catalyst is sufficiently high, defect-free zinc-blende structured InAs nanowires can be induced. This study provides an insight into the manipulation of crystal structure and structure quality of III-V semiconductor nanowires through catalyst engineering.