  We have fabricated superconductor-quantum dot-superconductor (SC-QD-SC)
junctions by using SC aluminum electrodes with narrow gaps laterally contacting
a single self-assembled InAs QD. The fabricated junctions exhibited clear
Coulomb staircases and Coulomb oscillations at 40 mK. Furthermore, clear
suppression in conductance was observed for the source-drain voltage $|V_{\rm
SD}| < 2\Delta/e$, where $\Delta$ is the SC energy gap of Al. The absence of
Josephson current that flows through QDs is due to the strong Coulomb
interaction and non-negligible thermal fluctuation in our measurement system.
