Morphology and composition controlled Ga_xIn_1-xSb nanowires: Understanding ternary antimonide growth

Antimonide-based nanowires represent an important new class of material with great promise for both fundamental physics studies and various device applications. We report a comprehensive study on understanding the growth behaviour of Ga_xIn_1-xSb nanowires on GaAs substrates using Au nanoparticles. First, the effect of growth parameters on the morphology and composition of Ga_xIn_1-xSb nanowires is extensively studied over the entire compositional range (from 3 to ∼100% of In). Second, the obtained compositional results are explained by a kinetic model, suggesting an Arrhenius-type behavior for the trimethylindium (TMIn) precursor. Third, the particle composition is fully investigated and the implications for growth are discussed with reference to our calculated Au-Ga-In phase diagram. Fourth, a mechanism is presented to explain the temperature-dependent morphology and radial growth of the Ga_xIn_1-xSb nanowires. Finally, we demonstrate homogeneous compositions in both axial and radial directions and the nanowires remain entirely twin-free zinc blende. The understanding gained from this study together with the potential to precisely tailor the band gap, wavelength and carrier mobilities allows fabrication of various Ga _xIn_1-xSb-based nanowire devices.