Shell structure and electron-electron interaction in self-assembled InAs quantum dots

M. Fricke; A. Lorke; J. P. Kotthaus; G. Medeiros-Ribeiro; P. M. Petroff

doi:doi:10.1209/epl/i1996-00210-x

Shell structure and electron-electron interaction in self-assembled InAs quantum dots DOI: 10.1209/epl/i1996-00210-x

Europhys. Lett, 36 (3), pp. 197-202 (1996)

Shell structure and electron-electron interaction in self-assembled InAs quantum dots

M. Fricke , A. Lorke , J. P. Kotthaus , G. Medeiros-Ribeiro and P. M. Petroff

Sektion Physik, LMU München - Geschwister-Scholl-Platz 1, 80539 München, Germany
Materials Department and QUEST, University of California, Santa Barbara, CA 93117, USA

(received 12 July 1996; accepted in final form 12 September 1996)

PACS. 73.23Hk - Coulomb blockade; single-electron tunneling.
PACS. 78.30Fs - III-V and II-VI semiconductors.
PACS. 78.66Fd - III-V semiconductors.

Abstract:

Using far-infrared spectroscopy, we investigate the excitations of self-organized InAs quantum dots as a function of the electron number per dot,

, which is monitored in situ by capacitance spectroscopy. Whereas the well-known two-mode spectrum is observed when the lowest (s-) states are filled, we find a rich excitation spectrum for

, which reflects the importance of electron-electron interaction in the present, strongly non-parabolic confining potential. From capacitance spectroscopy we find that the electronic shell structure in our dots gives rise to a distinct pattern in the charging energies which strongly deviates from the monotonic behavior of the Coulomb blockade found in mesoscopic or metallic structures.