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Accueil du site > Vie du laboratoire > Congrès / Colloques / Conférences > Optical Properties of Individual Nanowires and Quantum Dots in High Magnetic Field, Septembre 2014 > Programme du workshop > Abstract : Unintentional high density p-type modulation doping of a GaAs/AlAs core-multi-shell nanowire

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Abstract : Unintentional high density p-type modulation doping of a GaAs/AlAs core-multi-shell nanowire

P. Plochocka, J. Jadczak, A. Mitioglu, I. Breslavetz, M. Royo, A. Bertoni, G. Goldoni, T. Smolenski, P.

Kossacki, A. Kretinin, Hadas Shtrikman, and D. K. Maude

Achieving significant doping in GaAs/AlAs core/shell nanowires (NWs) is of considerable technological importance but remains a challenge due to the amphoteric behavior of the dopant atoms. Here we show that placing a narrow GaAs quantum well in the AlAs shell effectively getters residual carbon acceptors leading to unintentional p-type doping. Magneto-optical studies of such GaAs/AlAs core multi-shell NW reveal quantum confined emission, which is observed above the energy corresponding to the band gap of bulk GaAs. Such emission is absent in the optical spectra of single GaAs/AlAs core shell nanowires with comparable diameter [1]. Theoretical calculations of NW electronic structure confirm quantum confinement of carriers at the core/shell interface due to the presence of ionized carbon acceptors in the 1 nm GaAs layer in the shell. Micro-photoluminescence in high magnetic field shows a clear signature of avoided crossings of the n = 0 Landau level emission line with the n = 2 Landau level TO phonon replica. The coupling is caused by the resonant hole-phonon interaction, which is a fingerprint of the large 2D hole density in the structure.

[1] P. Plochocka et al. Nano Letters, 13, 2442, (2013)