Shell structure and electron-electron interaction in self-assembled InAs quantum dots
Sektion Physik, LMU München - Geschwister-Scholl-Platz 1,
80539 München, Germany
2 Materials Department and QUEST, University of California, Santa Barbara, CA 93117, USA
Accepted: 12 September 1996
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.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 78.30.Fs – III-V and II-VI semiconductors / 78.66.Fd – III-V semiconductors
© EDP Sciences, 1996