Abstract
Self-catalyzed AlGaAs nanowires (NWs) and NWs with a GaAs quantum dot (QD) were monolithically grown on Si(111) substrates via solid-source molecular beam epitaxy. This growth technique is advantageous in comparison to the previously employed Au-catalyzed approach, as it removes Au contamination issues and renders the structures compatible with complementary metal–oxide–semiconductor (CMOS) technology applications. Structural studies reveal the self-formation of an Al-rich AlGaAs shell, thicker at the NW base and thinning towards the tip, with the opposite behavior observed for the NW core. Wide alloy fluctuations in the shell region are also noticed. AlGaAs NW structures with nominal Al contents of 10, 20, and 30% have strong room temperature photoluminescence, with emission in the range of 1.50–1.72 eV. Individual NWs with an embedded 4.9 nm-thick GaAs region exhibit clear QD behavior, with spatially localized emission, both exciton and biexciton recombination lines, and an exciton line width of 490 μeV at low temperature. Our results demonstrate the properties and behavior of the AlGaAs NWs and AlGaAs/GaAs NWQDs grown via the self-catalyzed approach for the first time and exhibit their potential for a range of novel applications, including nanolasers and single-photon sources.
Highlights
Semiconductor nanowires (NWs) are promising building blocks for next-generation electronic and optoelectronic applications.[1]
Our results demonstrate the properties and behavior of the AlGaAs NWs and AlGaAs/GaAs nanowire-quantum dots (NWQDs) grown via the self-catalyzed approach for the first time and exhibit their potential for a range of novel applications, including nanolasers and single-photon sources
This allowed for the deposition of Ga and As only, which led to the formation of a GaAs segment of narrower band gap in the NW axis that inherently acts as a quantum dot (QD)
Summary
Semiconductor nanowires (NWs) are promising building blocks for next-generation electronic and optoelectronic applications.[1]. An essential step to expand the functionality range of NWs is the synthesis of ternary III−V alloys, allowing tunability of the band gap via the elemental composition. This provides an additional and controllable degree of freedom in the band-gap engineering[8] and has been widely employed in conventional thin-film growth. The band gap is direct up to 1.98 eV, which corresponds to an Al content of ∼45%.17 the planar GaAs/AlGaAs material system has led to a wide range of applications over the past few Received: April 24, 2021 Revised: June 11, 2021 Published: June 23, 2021
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