Self‐Catalyzed AlGaAs Nanowires and AlGaAs/GaAs Axial Heterostructures Grown by Molecular Beam Epitaxy

Self‐catalyzed AlGaAs nanowires (NWs) offer advantageous properties, including lattice matching to GaAs, a wide range of electronic bandgaps, and monolithic integration with the mature Si platform due to elastic strain relaxation. However, the growth of self‐catalyzed AlGaAs NWs is typically characterized by morphological challenges, such as branching and tapering. Here, we comprehensively investigate the optimization of the group III growth rate and V/III ratio. We demonstrate the growth of AlGaAs NWs using a Ga/Al alloy droplet as a co‐catalyst, achieving minimal branching and NW uniformity with up to 40% nominal Al content. Embedding a single GaAs segment in an optimized NW structure results in QD‐like properties, including strong spatially localized emission at room temperature. Our findings demonstrate the control of branching events in self‐catalyzed AlGaAs NWs, highlighting their potential for applications including nanolasers and quantum light emitters.