Issue
EPL
Volume 84, Number 5, December 2008
Article Number 57004
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/84/57004
Published online 26 November 2008
EPL, 84 (2008) 57004
DOI: 10.1209/0295-5075/84/57004

Observation of excited states in a p-type GaAs quantum dot

Y. 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

csontos@phys.ethz.ch

received 8 September 2008; accepted in final form 23 October 2008; published December 2008
published online 26 November 2008

Abstract
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 $T_{{\rm hole}}$ = 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.

PACS
73.63.Kv - Quantum dots.
73.23.Hk - Coulomb blockade; single-electron tunneling.
73.61.Ey - III–V semiconductors.

© EPLA 2008