<110>-growth orientation dependence of Ga2O3 nanowires on Cu3As seeds via vapor-solid-solid mechanism

Highlights: • Nonpolar<110>direction Ga₂O₃ Nanowires catalyzed by Cu₃As: insights into As layer epitaxy. • Control composition and interfacial abruptness in vapor-solid-solid nanowires. • Influences of growth temperature on the structural and growth mechanism of the Ga₂O₃ NWs were investigated via unique ternary alloy phase diagram. -- Abstract: To accurately control semiconductor nanowires' (NW) physical characteristics defining electronic, optical and sensor applications, it is necessary to understand their potential growth mechanism. In this study, the Ga₂O₃ NW growth orientation is found to be dependent on their Cu₃As catalyst structure via vapor-solid-solid (VSS) mechanism. The Ga₂O₃ NWs are synthesized by vapor transport method at 700 °C below the Cu₃As alloy eutectic temperature, which forms a solid structure on top of the NWs. The NWs have relatively uniform diameter of 40–60 nm and prefer to grow along<110>direction. Energy-dispersive X-ray spectroscopy (EDS) and high-resolution transmission electron microscope (HRTEM) data provide strong evidence that the harvested Ga₂O₃ NWs are epitaxially grown from Cu₃As-based (cubic and hexagonal) catalyst seeds. And Ga₂O₃{110} Cubic Cu₃As {₂10}, Ga₂O₃{110} Cubic Cu₃As {110} and Ga₂O₃ {110} hexagonal Cu₃As {110} have relatively low mismatch compared to other interface lattice planes, providing a key insight into the growth process according to the VSS mechanism. The thermodynamics driven composition changes in the growth process are elaborated in detail.