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HL: Halbleiterphysik
HL 35: Quantenpunkte und -dr
ähte: Optische Eigenschaften I
HL 35.5: Talk
Wednesday, March 26, 2003, 18:30–18:45, BEY/154
Microphotoluminescence studies on strain induced single quantum wires prepared by the cleaved edge overgrowth technique — •R. Schuster1, H. Hajak1, M. Reinwald1, W. Wegscheider1, D. Schuh2, M. Bichler2, and G. Abstreiter2 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany — 2Walter Schottky Institut, Technische Universität München, Am Coulombwall, 85748 Garching, Germany
Quantum wires (QWRs), which form at the T-shaped intersection of strained In0.2Al0.8As layers with large band gap and a GaAs quantum well (QW), exhibit large confinement energies of up to 40 meV. The polarization of these QWRs, which are based on a concept proposed by Grundmann et al. [1], is preferably oriented perpendicular to the GaAs QW. The samples were grown by molecular beam epitaxy using the cleaved edge overgrowth technique. In the first growth step 1 µm wide Al0.3Ga0.7As barriers were used to separate the In0.2Al0.8As stressor layers. This enables us to spatially resolve the photoluminescence signals from individual strained QWRs.
The confinement energy of the QWRs rises systematically with increasing thickness of the In0.2Al0.8As layer, since the biaxial strain of the [001] growth step is transmitted to the (110) GaAs QW. Atomic Force Microscopy surveys and X-ray studies in grazing incidence diffraction configuration are used to explain the difference between calculated and measured confinement energies. This work is supported by the Deutsche Forschungsgemeinschaft in the framework of SFB 348.
[1] M. Grundmann et al., Phys. Rev. B 61, 1744 (2000)