Formation of the axial heterojunction in GaSb/InAs(Sb) nanowires with high crystal quality

Switching of the group-III element in III-V nanowire heterostructures is difficult due to the high solubility of group-III atoms in the Au seed particle. In addition, switching from Sb to a different group-V element has not been achieved in binary materials, largely due to its high solubility in Au. In MOVPE growth the use of Sb precursors presents further complications due to reactor background contamination. In this paper we demonstrate growth of GaSb/InAs(Sb) nanowire heterostructures with potential applications in tunneling devices, and study the processes occurring during the transition from GaSb to InAs growth. We show how the heterostructure can be grown with a sharp transition by taking advantage of a growth stop, which occurs naturally as the Au seed particle is emptied of Ga and filled with In. The remaining Sb background in the reactor during the InAs growth results in a finite Sb incorporation into this segment. This has the advantage of suppressing stacking faults in the InAs(Sb) segment, making the entire heterostructure a single zincblende crystal.