Direct observation of interface and nanoscale compositional modulation in ternary III-As heterostructure nanowires

Straight, axial InAs nanowire with multiple segments of GaxIn1-xAs was grown. High resolution X-ray energy-dispersive spectroscopy (EDS) mapping reveals the distribution of group III atoms at the axial interfaces and at the sidewalls. Significant Ga enrichment, accompanied by a structural change is observed at the GaxIn1−xAs/InAs interfaces and a higher Ga concentration for the early grown GaxIn1−xAs segments. The elemental map and EDS line profile infer Ga enrichment at the facet junctions between the sidewalls. The relative chemical potentials of ternary alloys and the thermodynamic driving force for liquid to solid transition explains the growth mechanisms behind the enrichment.