GaAs/GaP quantum dots: Ensemble of direct and indirect heterostructures with room temperature optical emission
- Department of Physics, Humboldt-Universität zu Berlin, Newton-Str. 15, D-12489 Berlin (Germany)
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, D-12489 Berlin (Germany)
- Departamento de Fisica de la Materia Condensada, E.T.S.I.I., 47011 Valladolid GdSOptronlab, Dpto. Física de la Materia Condensada, Universidad de Valladolid, Ed. I+D, Paseo de Belén, 11, 47011, Valladolid (Spain)
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2A, 12489 Berlin (Germany)
We describe the optical emission and the carrier dynamics of an ensemble of self-assembled GaAs quantum dots embedded in GaP(001). The QD formation is driven by the 3.6% lattice mismatch between GaAs and GaP in the Stranski-Krastanow mode after deposition of more than 1.2 monolayers of GaAs. The quantum dots have an areal density between 6 and 7.6 × 10{sup 10} per cm{sup −2} and multimodal size distribution. The luminescence spectra show two peaks in the range of 1.7 and 2.1 eV. The samples with larger quantum dots have red emission and show less thermal quenching compared with the samples with smaller QDs. The large QDs luminescence up to room temperature. We attribute the high energy emission to indirect carrier recombination in the thin quantum wells or small strained quantum dots, whereas the low energy red emission is due to the direct electron-hole recombination in the relaxed quantum dots.
- OSTI ID:
- 22591411
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 10 Vol. 108; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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