Excitonic fine structure and binding energies of excitonic complexes in single InAs quantum dashes
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The fundamental electronic and optical properties of elongated InAs nanostructures embedded in quaternary InGaAlAs barrier are investigated by means of high-resolution optical spectroscopy and many-body atomistic tight-binding theory. These wire-like shaped self-assembled nanostructures are known as quantum dashes and are typically formed during the molecular beam epitaxial growth on InP substrates. In this work we study properties of excitonic complexes confined in quantum dashes emitting in a broad spectral range from below 1.2 to 1.55 μm. We find peculiar trends for the biexciton and negative trion binding energies, with pronounced trion binding in smaller size quantum dashes. These experimental findings are then compared and qualitatively explained by atomistic theory. The theoretical analysis shows a fundamental role of correlation effects for the absolute values of excitonic binding energies. Eventually, we determine the bright exciton fine structure splitting (FSS), where both the experiment and theory predict a broad distribution of the splitting varying from below 50 to almost 180 μeV. We identify several key factors determining the FSS values in such nanostructures including quantum dash size variation and composition fluctuations.
Mrowiński , P , Zieliński , M , Świderski , M , Misiewicz , J , Somers , A , Reithmaier , J P , Höfling , S & Sęk , G 2016 , ' Excitonic fine structure and binding energies of excitonic complexes in single InAs quantum dashes ' , Physical Review. B, Condensed matter and materials physics , vol. 94 , no. 11 , 115434 . https://doi.org/10.1103/PhysRevB.94.115434
Physical Review. B, Condensed matter and materials physics
© 2016, American Physical Society. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1103/PhysRevB.94.115434