文摘
Here we report on the Ga self-catalyzed growth of near full-composition-range energy-gap-tunable GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires by molecular-beam epitaxy. GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires with different Sb content are systematically grown by tuning the Sb and As fluxes, and the As background. We find that GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires with low Sb content can be grown directly on Si(111) substrates (0 ≤ <i>xi> ≤ 0.60) and GaAs nanowire stems (0 ≤ <i>xi> ≤ 0.50) by tuning the Sb and As fluxes. To obtain GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires with <i>xi> ranging from 0.60 to 0.93, we grow the GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires on GaAs nanowire stems by tuning the As background. Photoluminescence measurements confirm that the emission wavelength of the GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires is tunable from 844 nm (GaAs) to 1760 nm (GaAs<sub>0.07sub>Sb<sub>0.93sub>). High-resolution transmission electron microscopy images show that the grown GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires have pure zinc-blende crystal structure. Room-temperature Raman spectra reveal a redshift of the optical phonons in the GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires with <i>xi> increasing from 0 to 0.93. Field-effect transistors based on individual GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires are fabricated, and rectifying behavior is observed in devices with low Sb content, which disappears in devices with high Sb content. The successful growth of high-quality GaAs<sub>1–<i>xi>sub>Sb<sub><i>xi>sub> nanowires with near full-range bandgap tuning may speed up the development of high-performance nanowire devices based on such ternaries.