Control of tunnel coupling strength between InAs quantum dots and nanogap metallic electrodes through In-Ga intermixing

We have investigated the growth-temperature, TG, dependence of the electronic properties of single self-assembled InAs quantum dots (QDs) coupled to nanogap metallic electrodes. The orbital quantization energies of QDs and the tunnel resistances exhibited strong TG-dependence due to In-Ga intermixing during QD formation. It was found that the transparency of the tunnel junctions is controllable over a very wide range by simply changing the size and the growth temperature of QDs. By realizing strong QD-electrodes coupling, very high Kondo temperature TK∼80 K was observed in our InAs QD system.