Near Full-Composition-Range High-Quality GaAs_1-xSb_x Nanowires Grown by Molecular-Beam Epitaxy.

Abstract

Here we report on the Ga self-catalyzed growth of near full-composition-range energy-gap-tunable GaAs_1-xSb_x nanowires by molecular-beam epitaxy. GaAs_1-xSb_x nanowires with different Sb content are systematically grown by tuning the Sb and As fluxes, and the As background. We find that GaAs_1-xSb_x 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 GaAs_1-xSb_x nanowires with x ranging from 0.60 to 0.93, we grow the GaAs_1-xSb_x nanowires on GaAs nanowire stems by tuning the As background. Photoluminescence measurements confirm that the emission wavelength of the GaAs_1-xSb_x nanowires is tunable from 844 nm (GaAs) to 1760 nm (GaAs_0.07Sb_0.93). High-resolution transmission electron microscopy images show that the grown GaAs_1-xSb_x nanowires have pure zinc-blende crystal structure. Room-temperature Raman spectra reveal a redshift of the optical phonons in the GaAs_1-xSb_x nanowires with x increasing from 0 to 0.93. Field-effect transistors based on individual GaAs_1-xSb_x 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_1-xSb_x nanowires with near full-range bandgap tuning may speed up the development of high-performance nanowire devices based on such ternaries.