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

A Two-Step Growth Pathway for High Sb Incorporation in GaAsSb Nanowires in the Telecommunication Wavelength Range

“…Even though there is an extensive body of literature on Au-catalyzed and Au-free axial GaAsSb NWs 12–23 , the majority of the work on self-assisted axial GaAsSb NWs is mainly focused on structural and electronic characterization. Despite the fact that in the axial configuration an Sb composition as high as 93 at.% has been reported 9 , Sb compositions beyond 30 at.% have a detrimental impact on NW morphology and characteristics, namely uneven growth, tapered morphology, multiple facets, compositional gradient, thick parasitic islands of GaAsSb and poor PL emission 9, 12, 19–21 .…”

“…GaAsSb NWs can be grown in both axial and core-shell architectures. One of the favorable attributes of GaAsSb NWs is that the NWs exhibit pure ZB crystal structure over the entire composition range 9 . Bandgap tuning corresponding to the desirable wavelength of 1.3 µm in the telecommunication window has been demonstrated 10, 11 with a core-shell configuration.…”

Brief Review of Epitaxy and Emission Properties of GaSb and Related Semiconductors

“…By growth of the AlGaAs passive layer, Dingding Ren et al realized for the first time the wavelength tunability of the optical emission from self-catalyzed GaAsSb nanowire arrays, and a tuning range from 1.219 to 1.422 eV [80]. Recently, by tuning of the background As, Li et al realized near-full composition range GaAsSb NWs (GaAs 1−x Sb x nanowires with x ranging from 0.60 to 0.93), and the emission wavelength of these GaAsSb NWs was tunable from 844 nm to 1760 nm [5]. Moreover, Dheeraj et al demonstrated for GaAs NWs with GaAsSb inserted, the band alignment was a staggered type II (as shown Figure 15) [88].…”

“…Groups III-V semiconductors are the most promising candidate infrared materials for use in lasers and detectors, owing to their high absorption coefficients, high carrier mobilities and widely tunable band gaps [1,4]. Among these materials, gallium antimonide (GaSb)-based alloys and compounds offer a wide range of electronic band gaps, band gap offsets and electronic barriers along with extremely high electron mobility; these materials would thus enable a variety of devices that are much faster than the equivalent InP-and GaAs-based devices and infrared light sources, and would facilitate lower power consumption [5,6]. Therefore, GaSb materials in the forms of epitaxial layers, multi-element alloys, quantum wells, superlattices and low-dimensional nanostructures have been attracting considerable attention.…”

“…To date, the growth of GaSb-based semiconductors has mainly been dependent on liquid phase epitaxy (LPE), metal-organic chemical vapor deposition (MOCVD), and molecular beam epitaxy (MBE). MBE is preferred as a high-efficiency epitaxial growth technique that is used to manufacture light-emitting diodes, lasers, and detectors for MIR waveband operation by varying the material components to adjust their energy bands [1,5,7]. By tuning of the growth parameters, a variety of complex quantum structures with high surface and interface quality can be realized.…”