Near Full-Composition-Range High-Quality GaAs1–xSbx Nanowires Grown by Molecular-Beam Epitaxy

Here we report on the Ga self-catalyzed growth of near full-composition-range energy-gap-tunable GaAs1–xSbx nanowires by molecular-beam epitaxy. GaAs1–xSbx nanowires with different Sb content are systematically grown by tuning the Sb and As fluxes, and the As background. We find that GaAs1–xSbx nanowires with low Sb content can be grown directly on Si(111) substrates (0 ≤ x ≤ 0.60) and GaAs nanowire stems (0 ≤ x ≤ 0.50) by tuning the Sb and As fluxes. To obtain GaAs1–xSbx nanowires with x ranging from 0.60 to 0.93, we grow the GaAs1–xSbx nanowires on GaAs nanowire stems by tuning the As background. Photoluminescence measurements confirm that the emission wavelength of the GaAs1–xSbx nanowires is tunable from 844 nm (GaAs) to 1760 nm (GaAs0.07Sb0.93). High-resolution transmission electron microscopy images show that the grown GaAs1–xSbx nanowires have pure zinc-blende crystal structure. Room-temperature Raman spectra reveal a redshift of the optical phonons in the GaAs1–xSbx nanowires with x increasing fro...