High-quality InAs/InSb nanowire heterostructures grown by metal-organic vapor-phase epitaxy

Planar growth of high-quality InAs/InSb heterostructure nanowires by metal-organic vapor-phase epitaxy was demonstrated. The nanowires are found to consists of two-segment structure with a narrow base diameter and a wide upper-segment diameter. The InAs crystal structures show a very low density of stacking faults and the interface of InAs and InSb is atomically sharp as the lattice-fringe separation to the interface changes at the interface. Point analysis of the InAs segment gives a 49.5 to 50.5 ratio (∓0.6) between indium and arsenic, with no trace of any other material. It is found that the difference in indium concentration in the particle from 30 to 67 atomic percent would lead to an increase of the particle diameter of 35%. The 40-nm-long InAs zinc blende segment is present below the InAs/InSb interface and is thus assumed to correspond to the gas-switching sequence from arsenic to TMSb.