Crystal Phase Engineering in Self-Assisted GaAs Nanowires

The study focuses on the significance of cubic Zinc-BlendeZinc-blende (ZB) and hexagonal wurtziteWurtzite (WZ) structures in GaAsGaAs nanowiresNanowire. GaAs typically crystallizes in the ZB structure in its bulk phase, while the WZ phase is observed only in NWs. This structural variation is crucial for applications like integrated light sources on silicon. However, the gold-catalyzed growth method for WZ GaAsGaAs NWs is incompatible with silicon electronics due to gold-induced trap states, necessitating a self-assisted growth method to avoid contamination. Recent advancements in molecular beam epitaxyEpitaxy (MBE) have enabled the controlled formation of WZ phases inSelf-assisted GaAs self-assisted GaAsGaAs NWs. The chapter highlights the use of reflection high-energy electron diffraction (RHEED) for real-time monitoring of ZB and WZ phase growth. The nucleationNucleation mechanisms, influenced by the catalyst droplet’s size and contact angle, are explored, establishing critical angles for phase determination. The chapter is divided into experimental results utilizing RHEED for WZ structure formation and a growth model to estimate the contact angle of the liquid phase. The findings underscore the potential for controlled WZ segment growth, supported by numerical simulations.