Correlated nanoscale analysis of the emission from wurtzite versus zincblende (In,Ga)As/GaAs nanowire core-shell quantum wells

Abstract

While the properties of wurtzite GaAs have been extensively studied during the past decade, little is known about the influence of the crystal polytype on ternary (In,Ga)As quantum well structures. We address this question with a unique combination of correlated, spatially-resolved measurement techniques on core-shell nanowires that contain extended segments of both the zincblende and wurtzite polytypes. Cathodoluminescence hyperspectral imaging reveals a blueshift of the quantum well emission energy by $75\pm 15$ meV in the wurtzite polytype segment. Nanoprobe x-ray diffraction and atom probe tomography enable $\mathbf{k}\cdot \mathbf{p}$ calculations for the specific sample geometry to reveal two comparable contributions to this shift. First, there is a 30% drop in In mole fraction going from the zincblende to the wurtzite segment. Second, the quantum well is under compressive strain, which has a much stronger impact on the hole ground state in the wurtzite than in the zincblende segment. Our results highlight the role of the crystal structure in tuning the emission of (In,Ga)As quantum wells and pave the way to exploit the possibilities of three-dimensional bandgap engineering in core-shell nanowire heterostructures. At the same time, we have demonstrated an advanced characterization toolkit for the investigation of semiconductor nanostructures.

This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Nano Letters (2019), copyright (C) American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.nanolett.9b01241, the supporting information is available (free of charge) under the same link

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Cited by in corpus (4)

• Coaxial GaAs/(In,Ga)As dot-in-a-well nanowire heterostructures for electrically driven infrared light generation on Si in the telecommunication O band
• Beam damage of single semiconductor nanowires during X-ray nano beam diffraction experiments
• Spatially-resolved luminescence and crystal structure of single core-shell nanowires measured in the as-grown geometry
• Composition and optical properties of (In,Ga)As nanowires grown by group-III-assisted molecular beam epitaxy