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Piezoelectric Effects on the Electron–Hole Dipole in In 0.5 Ga 0.5 As/GaAs Self‐Assembled Quantum Dots
Author(s) -
Levin A.,
Patanè A.,
Schindler F.,
Polimeni A.,
Eaves L.,
Main P.C.,
Henini M.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200103)224:1<37::aid-pssb37>3.0.co;2-v
Subject(s) - quantum dot , condensed matter physics , dipole , photocurrent , electron , piezoelectricity , quantum confined stark effect , stark effect , electric field , spectroscopy , physics , optoelectronics , quantum mechanics , acoustics
Photocurrent spectroscopy is used to investigate the quantum‐confined Stark shift, QCSS, of In 0.5 Ga 0.5 As/GaAs self‐assembled quantum dots (QDs) grown on (100) and (311)B planes. An asymmetric dependence of the QCSS with respect to the direction of the electric field is observed in both cases. We show that the (100) dots have an almost zero permanent electron–hole dipole moment. This result indicates that the recently reported “inverted electron–hole alignment” [Phys. Rev. Lett. 84 , 733 (2000)] is not a general property of QDs. By comparing the QCSS for the (100) and (311)B dots, we propose that in the dots grown on the high index plane, the electron and hole wavefunctions are displaced by a strain‐induced piezoelectric field.