EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The formation of III-V semiconductor nanowire (NW) heterostructures as building blocks for advanced electronic and optoelectronic devices is a major goal of the NW community. However, strategies to realise complex III-V semiconductor NW heterostructures solely by the metal-assisted growth and going beyond the axial arrangement of the segments are rare. In this contribution, we report the formation of biaxial III-V semiconductor NW heterostructures using two-phase nanoparticles as growth promoters. For that purpose, Ag-Cu nanoparticles generated in a spark discharge generator were deposited on a heating chip for in situ transmission electron microscopy (TEM) investigations. Subsequently, the chip was transferred into the environmental transmission electron microscope (ETEM) at Lund University, which enables the supply of metalorganic precursors for III-V semiconductors to the heated area of the chip. We investigated basic processes before and during the growth of biaxial InP-InAs_1-xP_x NW heterostructures via high-resolution TEM imaging, high frame rate TEM movies and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy. Particularly, we found evidence of the presence of Cu₃P and an Ag-In alloy on the tip of the NW heterostructure. This allowed deeper insight into the growth mechanism, which involves a strong interaction between the Ag- and the Cu-rich phase. The findings of our study underscore the suitability of two-phase nanoparticles as growth promoters for complex NW heterostructures and thus demonstrate an innovative attempt to exploit the full potential of metal-assisted NW growth.