Morphological Evolution of Self-Catalyzed III−V Ternary Nanowires

Self-catalyzed III−V nanowires (NWs) present an interesting example of a system with one degree of freedom, where the NW radius can either gradually increase or self-equilibrate to a stable size depending on the V/III influx imbalance. This effect is well-known for binary NWs but was never studied for ternary NWs. Herein, we consider the morphological evolution of III−V ternary NWs based on group V intermix using a refined approach that takes into account the initial growth stage with the full collection of group III adatoms from the entire NW length. Due to different incorporation rates of dissimilar group V species, the V/III influx imbalance and the corresponding stable radius become dependent on the NW composition. The self-equilibration effect on the NW radius remains in ternary NWs, but the morphological evolution becomes more complex and composition-dependent. We find three distinct NW growth stages, with the initial shrinkage of the radius, followed by its quasi-linear increase with length, and self-equilibration for lengths exceeding the diffusion length of group III adatoms. These results are in agreement with the data on GaPxAs1−x NWs and InAs/InP NW heterostructures, and should be useful for the morphological design of these complex structures.