We have determined the main parameters of the quasi-one-dimensional excitons confined in GaAs V-shaped quantum wires, namely exciton Bohr radius and binding energy, by two-photon absorption and magnetoluminescence experiments. The experimental results are in excellent agreement with our calculations, based on realistic wave functions for the actual wire geometry.

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The incorporation of In in the growth of crescent-shaped In0.12Ga0.88As quantum wires embedded in (AlAs)4(GaAs)8 superlattice barriers is studied in atomic detail using cross-sectional scanning tunneling microscopy. It is found that the In distribution in both the surface and the first subsurface layer can be atomically resolved in the empty- and filled-state images, respectively. Strong In segregation is seen at the InGaAs/GaAs interfaces, but neither an expected enhancement of the In concentration at the center of the quantum wire compared to the planar quantum well nor In clustering beyond the statistical expectation is observed.

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Strong evidence for amphoteric native defect reactions is obtained by photoluminescence analysis of Si-doped GaAs samples (n≈1.5×1018 cm−3) annealed under different conditions. Annealing in excess As4 vapor creates a large concentration of Ga vacancies, making possible the transformation of this defect into an As vacancy and an As antisite defect. Similarly, As vacancies generated at high concentration during annealing under Ga-rich conditions are transformed into Ga vacancies and Ga antisite defects. Photoluminescence intensities associated with the corresponding defects are in qualitative agreement with the predictions of the mass action law applied to the amphoteric native defect reactions.