title: Enhanced luminescence properties of InAs-InAsP core-shell nanowires.
abstract: Utilizing narrow band gap nanowire (NW) materials to extend nanophotonic applications to the mid-infrared spectral region (>2-3 μm) is highly attractive, however, progress has been seriously hampered due to their poor radiative efficiencies arising from nonradiative surface and Auger recombination. Here, we demonstrate up to ~ 10(2) times enhancements of the emission intensities from InAs NWs by growing an InAsP shell to produce core-shell NWs. By systematically varying the thickness and phosphorus (P)-content of the InAsP shell, we demonstrate the ability to further tune the emission energy via large strain-induced peak shifts that already exceed >100 meV at comparatively low fractional P-contents. Increasing the P-content is found to give rise to additional line width broadening due to asymmetric shell growth generated by a unique transition from {110}- to {112}-sidewall growth as confirmed by cross-sectional scanning transmission electron microscopy. The results also elucidate the detrimental effects of plastic strain relaxation on the emission characteristics, particularly in core-shell structures with very high P-content and shell thickness. Overall, our findings highlight that enhanced mid-infrared emission efficiencies with effective carrier confinement and suppression of nonradiative recombination are highly sensitive to the quality of the InAs-InAsP core-shell interface.
authors.affiliation: Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München , Am Coulombwall 4, Garching, 85748, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Treu
authors.forename: Michael
authors.initials: M
authors.lastname: Bormann
authors.forename: Hannes
authors.initials: H
authors.lastname: Schmeiduch
authors.forename: Markus
authors.initials: M
authors.lastname: Döblinger
authors.forename: Stefanie
authors.initials: S
authors.lastname: Morkötter
authors.forename: Sonja
authors.initials: S
authors.lastname: Matich
authors.forename: Peter
authors.initials: P
authors.lastname: Wiecha
authors.forename: Kai
authors.initials: K
authors.lastname: Saller
authors.forename: Benedikt
authors.initials: B
authors.lastname: Mayer
authors.forename: Max
authors.initials: M
authors.lastname: Bichler
authors.forename: Markus-Christian
authors.initials: MC
authors.lastname: Amann
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Finley
authors.forename: Gerhard
authors.initials: G
authors.lastname: Abstreiter
authors.forename: Gregor
authors.initials: G
authors.lastname: Koblmüller
mesh_terms: D001152:Arsenicals / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D049449:Luminescence; D057145:Nanoshells / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry; D053770:Nanowires / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001152:Arsenicals; D007204:Indium; C076773:indium arsenide; D012825:Silicon