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.
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