  We have fabricated single electron tunneling structures by forming nanogap
metallic electrodes directly upon single self-assembled InAs quantum dots
(QDs). The fabricated samples exhibited clear Coulomb blockade effects.
Furthermore, a clear Kondo effect was observed when strong coupling between the
electrodes and the QDs was realized using a large QD with a diameter of ~ 100
nm. From the temperature dependence of the linear conductance at the Kondo
valley, the Kondo temperature TK was determined to be ~ 81 K. This is the
highest TK ever reported for artificial quantum nanostructures.
