At ambient conditions, GaAs forms in the zincblende (ZB) phase with the notable exception of nanowires (NWs) where the wurtzite (WZ) lattice is also found. The WZ formation is both a complication to be dealt with and a potential feature to be exploited, for example, in NW homostructures wherein ZB and WZ phases alternate controllably and thus band gap engineering is achieved. Despite intense studies, some of the fundamental electronic properties of WZ GaAs NWs are not fully assessed yet. In this work, by using photoluminescence (PL) under high magnetic fields (B = 0−28 T), we measure the diamagnetic shift, ΔEd, and the Zeeman splitting of the band gap free exciton in WZ GaAs formed in core−shell InGaAs−GaAs NWs. The quantitative analysis of ΔEd at different temperatures (T = 4.2 and 77 K) and for different directions of B⃗ allows the determination of the exciton reduced mass, μexc, in planes perpendicular (μexc = 0.052 m0, where m0 is the electron mass in vacuum) and parallel (μexc = 0.057 m0) to the ĉ axis of the WZ lattice. The value and anisotropy of the exciton reduced mass are compatible with the electron lowest-energy state having Γ7C instead of Γ8C symmetry. This finding answers a long discussed issue about the correct ordering of the conduction band states in WZ GaAs. As for the Zeeman splitting, it varies considerably with the field direction, resulting in an exciton gyromagnetic factor equal to 5.4 and ∼0 for B⃗//ĉand B⃗⊥ĉ, respectively. This latter result provides fundamental insight into the band structure of wurtzite GaAs.

Addressing the Fundamental Electronic Properties of Wurtzite GaAs Nanowires by High-Field Magneto-Photoluminescence Spectroscopy / De Luca, Marta; Rubini, Silvia; Felici, Marco; Meaney, Alan; Christianen, Peter C. M.; Martelli, Faustino; Polimeni, Antonio. - In: NANO LETTERS. - ISSN 1530-6984. - 17:11(2017), pp. 6540-6547. [10.1021/acs.nanolett.7b02189]

Addressing the Fundamental Electronic Properties of Wurtzite GaAs Nanowires by High-Field Magneto-Photoluminescence Spectroscopy

De Luca, Marta
Membro del Collaboration Group
;
Felici, Marco
Membro del Collaboration Group
;
Polimeni, Antonio
Supervision
2017

Abstract

At ambient conditions, GaAs forms in the zincblende (ZB) phase with the notable exception of nanowires (NWs) where the wurtzite (WZ) lattice is also found. The WZ formation is both a complication to be dealt with and a potential feature to be exploited, for example, in NW homostructures wherein ZB and WZ phases alternate controllably and thus band gap engineering is achieved. Despite intense studies, some of the fundamental electronic properties of WZ GaAs NWs are not fully assessed yet. In this work, by using photoluminescence (PL) under high magnetic fields (B = 0−28 T), we measure the diamagnetic shift, ΔEd, and the Zeeman splitting of the band gap free exciton in WZ GaAs formed in core−shell InGaAs−GaAs NWs. The quantitative analysis of ΔEd at different temperatures (T = 4.2 and 77 K) and for different directions of B⃗ allows the determination of the exciton reduced mass, μexc, in planes perpendicular (μexc = 0.052 m0, where m0 is the electron mass in vacuum) and parallel (μexc = 0.057 m0) to the ĉ axis of the WZ lattice. The value and anisotropy of the exciton reduced mass are compatible with the electron lowest-energy state having Γ7C instead of Γ8C symmetry. This finding answers a long discussed issue about the correct ordering of the conduction band states in WZ GaAs. As for the Zeeman splitting, it varies considerably with the field direction, resulting in an exciton gyromagnetic factor equal to 5.4 and ∼0 for B⃗//ĉand B⃗⊥ĉ, respectively. This latter result provides fundamental insight into the band structure of wurtzite GaAs.
2017
band-structure; effective mass; exciton; GaAs nanowires; gyromagnetic factor; magneto-photoluminescence spectroscopy; wurtzite; Bioengineering; Chemistry (all); Materials Science (all); Condensed Matter Physics; Mechanical Engineering
01 Pubblicazione su rivista::01a Articolo in rivista
Addressing the Fundamental Electronic Properties of Wurtzite GaAs Nanowires by High-Field Magneto-Photoluminescence Spectroscopy / De Luca, Marta; Rubini, Silvia; Felici, Marco; Meaney, Alan; Christianen, Peter C. M.; Martelli, Faustino; Polimeni, Antonio. - In: NANO LETTERS. - ISSN 1530-6984. - 17:11(2017), pp. 6540-6547. [10.1021/acs.nanolett.7b02189]
File allegati a questo prodotto
File Dimensione Formato  
De Luca_Addressing_2017.pdf

solo gestori archivio

Tipologia: Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 1.42 MB
Formato Adobe PDF
1.42 MB Adobe PDF   Contatta l'autore

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1067702
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 10
  • ???jsp.display-item.citation.isi??? 10
social impact