Photocurrent spectroscopy is used to investigate the quantum-confined Stark shift, QCSS, of In0.5Ga0.5As/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.
Piezoelectric effects on the electron-hole dipole in In0.5Ga0.5As/GaAs self-assembled quantum dots / A., Levin; A., Patane; F., Schindler; Polimeni, Antonio; L., Eaves; P. C., Main; M., Henini. - In: PHYSICA STATUS SOLIDI B-BASIC RESEARCH. - ISSN 0370-1972. - STAMPA. - 224:1(2001), pp. 37-40. [10.1002/1521-3951(200103)224:1<37::aid-pssb37>3.0.co;2-v]
Piezoelectric effects on the electron-hole dipole in In0.5Ga0.5As/GaAs self-assembled quantum dots
POLIMENI, Antonio;
2001
Abstract
Photocurrent spectroscopy is used to investigate the quantum-confined Stark shift, QCSS, of In0.5Ga0.5As/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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
