Electronic structure, morphology and emission polarization of enhanced symmetry InAs quantum-dot-like structures grown on InP substrates by molecular beam epitaxy
2013; American Institute of Physics; Volume: 114; Issue: 9 Linguagem: Inglês
10.1063/1.4820517
ISSN1520-8850
AutoresA. Maryński, G. Sȩk, Anna Musiał, J. Andrzejewski, J. Misiewicz, C. Gilfert, Johann Peter Reithmaier, Amir Capua, Ouri Karni, David Gready, G. Eisenstein, Galit Atiya, Wayne D. Kaplan, Sebastian Kölling,
Tópico(s)Electronic and Structural Properties of Oxides
ResumoThe optical and structural properties of a new kind of InAs/InGaAlAs/InP quantum dot (QD)-like objects grown by molecular beam epitaxy have been investigated. These nanostructures were found to have significantly more symmetrical shapes compared to the commonly obtained dash-like geometries typical of this material system. The enhanced symmetry has been achieved due to the use of an As2 source and the consequent shorter migration length of the indium atoms. Structural studies based on a combination of scanning transmission electron microscopy (STEM) and atom probe tomography (APT) provided detailed information on both the structure and composition distribution within an individual nanostructure. However, it was not possible to determine the lateral aspect ratio from STEM or APT. To verify the in-plane geometry, electronic structure calculations, including the energy levels and transition oscillator strength for the QDs have been performed using an eight-band k·p model and realistic system parameters. The results of calculations were compared to measured polarization-resolved photoluminescence data. On the basis of measured degree of linear polarization of the surface emission, the in-plane shape of the QDs has been assessed proving a substantial increase in lateral symmetry. This results in quantum-dot rather than quantum-dash like properties, consistent with expectations based on the growth conditions and the structural data.
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