Towards the understanding of the gold interaction with AIII-BV semiconductors at the atomic level

AIII-BV semiconductors have been considered to be a promising material for decades in overcoming the limitations of silicon semiconductor devices. One of the important aspects within the AIII-BV semiconductor technology is gold-semiconductor interactions on the nanoscale. We report on the investigations into the basic chemical interactions of Au atoms with AIII-BV semiconductor crystals by the investigation of the nanostructure formation in the process of thermally-induced Au self-assembly on various AIII-BV surfaces by means of atomically resolved High Angle Annular Dark Field (HAADF) Scanning Transmission Electron Microscopy (STEM) measurements. We have found that the formation of nanostructures is a consequence of the surface diffusion and nucleation of adatoms produced by Au induced chemical reactions on AIII-BV semiconductor surfaces. Only for InSb crystals we have found that there is efficient diffusion of Au atoms into the bulk, which we experimentally studied by Machine Learning HAADF STEM image quantification and theoretically by Density Functional Theory (DFT) calculations with the inclusion of finite temperature effects. Furthermore, the effective number of Au atoms needed to release one AIII metal atom has been estimated. The experimental finding reveals a difference in the Au interactions with the In- and Ga-based groups of AIII-BV semiconductors. Our comprehensive and systematic studies uncover the details of the Au interactions with the AIII-BV surface at the atomic level with chemical sensitivity and shed new light on the fundamental Au/AIII-BV interactions at the atomic scale.