Early-stage nucleation and growth of self-catalyzed GaAs nanowires on Si(111) with interfacial strain near pinholes

Abstract The nucleation and early-stage growth of self-catalyzed GaAs nanowires (NWs) on Si(111) substrates via the vapor–liquid–solid mechanism using molecular beam epitaxy were investigated. By analyzing NWs from the initial nucleation stage to several micrometers in length, the growth evolution and the potential influence of pinholes in the native oxide layer on Si during the earliest nucleation stages were examined. High-resolution scanning transmission electron microscopy (STEM) provided a detailed spatial characterization of the strain state at the GaAs-Si interface with pinholes. STEM analysis suggests that lattice strain facilitates a smooth transition between the GaAs formed around the pinhole and the Si substrate, supporting favorable epitaxial growth. These findings offer insights into the strain environment at the GaAs-Si interface, contributing to improved control over the integration of self-catalyzed III–V semiconductors on Si.