Single electron transistors using single self-assembled InAs quantum dots

Abstract. The electron transport through single self-assembled InAs quantum dots (QDs) grown on GaAs surfaces has been investigated by using metallic leads with narrow gaps. Clear Coulomb staircases and Coulomb gaps have been observed at 4.2 K. Coulomb blockade oscillation which reflects single electron charging in the QDs was also observed when a backgate voltage was swept. It is found that uncapped as-grown InAs QDs with diameter o f approximately 50 nm contain electrons without applying a gate bias.