Phase separation induced by Au catalysts in ternary InGaAs nanowires

Abstract

We report a novel phase separation phenomenon observed in the growth of ternary InxGa1-xAs nanowires by metalorganic chemical vapor deposition. A spontaneous formation of core-shell nanowires is investigated by cross-sectional transmission electron microscopy, revealing the compositional complexity within the ternary nanowires. It has been found that for InxGa1-xAs nanowires high precursor flow rates generate ternary InxGa1-xAs cores with In-rich shells, while low precursor flow rates produce binary GaAs cores with ternary In xGa1-xAs shells. First-principle calculations combined with thermodynamic considerations suggest that this phenomenon is due to competitive alloying of different group-III elements with Au catalysts, and variations in elemental concentrations of group-III materials in the catalyst under different precursor flow rates. This study shows that precursor flow rates are critical factors for manipulating Au catalysts to produce nanowires of desired composition. Show more