Selective GaSb radial growth on crystal phase engineered InAs nanowires.

In this work we have developed InAs nanowire templates, with designed zinc blende and wurtzite segments, for selective growth of radial GaSb heterostructures using metal organic vapor phase epitaxy. We find that the radial growth rate of GaSb is determined by the crystal phase of InAs, and that growth is suppressed on InAs segments with a pure wurtzite crystal phase. The morphology and the thickness of the grown shell can be tuned with full control by the growth conditions. We demonstrate that multiple distinct core-shell segments can be designed and realized with precise control over their length and axial position. Electrical measurements confirm that suppression of shell growth is possible on segments with wurtzite structures. This growth method enables new functionalities in structures formed by using bottom-up techniques, with complexity beyond that attainable by using top-down techniques.