1. Built-in elastic strain and localization effects on GaAs luminescence of MOVPE-grown GaAs-AlGaAs core-shell nanowires
- Author
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Prete, Paola, Miccoli, Ilio, Marzo, Fabio, Lovergine, Nico, Prete, Paola, Miccoli, Ilio, Marzo, Fabio, and Lovergine, Nicola
- Subjects
Condensed Matter::Materials Science ,excitons ,AlGaAs ,GaAs ,elastic strain ,photoluminescence ,Exciton localization ,core-shell nanowire ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,III-V Semiconductor ,Elastic strain ,core-shell nanowires ,Photoluminescence - Abstract
The core photoluminescence emission of MOVPE-grown GaAs-Al0.33Ga0.67As core-shell nanowires is studied as function of the relevant geometrical parameter of these nanostructures, namely the shell-thickness to core-radius ratio hs/Rc. The energy of the dominant emission peak was compared with values of the GaAs heavy- and light-hole excitons redshifted by a uniaxial tensile strain, the latter calculated assuming perfect coherence at the core/shell interface and elastic energy equilibrium within the nanowires. Good agreement is obtained for hs/Rc < 1, the intrinsic strain-free excitonic emission being identified at 1.510 eV, and further ascribed to bound heavy-hole excitons. For hs/Rc > 1 increasingly larger redshifts (up to ∼9 meV in excess of values calculated based on our elastic strain model) are observed, and tentatively ascribed to shell-dependent exciton localization effects. Experimental and calculated bound exciton peak energies for GaAs-Al0.33Ga0.67As core-shell nanowires as function of their shell-thickness to core-radius ratio hs/Rc.
- Published
- 2013