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.