Observation of excited states in a p-type GaAs quantum dotY. Komijani1, M. Csontos1, T. Ihn1, K. Ensslin1, D. Reuter2 and A. D. Wieck2
1 Solid State Physics Laboratory, ETH Zürich - 8093 Zürich, Switzerland
2 Angewandte Festkörperphysik, Ruhr-Universität Bochum - 44780 Bochum, Germany, EU
received 8 September 2008; accepted in final form 23 October 2008; published December 2008
published online 26 November 2008
A quantum dot fabricated by scanning probe oxidation lithography on a p-type, C-doped GaAs/AlGaAs heterostructure is investigated by low-temperature electrical conductance measurements. Clear Coulomb blockade oscillations are observed and analyzed in terms of sequential tunneling through the single-particle levels of the dot at = 185 mK. The charging energies as large as ~ 2 meV evaluated from Coulomb diamond measurements together with the well-resolved single-hole excited-state lines in the charge stability diagram indicate that the dot is operated with a small number of confined particles close to the ultimate single-hole regime.
73.63.Kv - Quantum dots.
73.23.Hk - Coulomb blockade; single-electron tunneling.
73.61.Ey - III–V semiconductors.
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