Formation of quasi-two-dimensional layers of bismuth nanoparticles in epitaxial layers of gallium arsenide

By delta-doping gallium arsenide layers with bismuth during low-temperature molecular beam epitaxy (MBE) followed by annealing, quasi-two-dimensional layers of bismuth nanoparticles were obtained in a matrix of epitaxial gallium arsenide. The low epitaxy temperature ensures the formation of a high concentration of nonstoichiometric defects in the material, primarily antisite defects [As$_{\mathrm{Ga}}$] and gallium vacancies. The migration of these defects during annealing leads to the formation of both small precipitates in the LT-GaAs layers and larger nanoinclusions enriched with bismuth, located on the Bi delta layers.