Effect of In–Ga intermixing on the electronic states in self-assembled InAs quantum dots probed by nanogap electrodes

Shibata, K.; Jung, M.; Cha, K. M.; Sotome, M.; Hirakawa, K.
April 2009
Applied Physics Letters;4/20/2009, Vol. 94 Issue 16, p162107
Academic Journal
We have investigated the effect of In–Ga intermixing on the electronic states in single self-assembled InAs quantum dots (QDs) coupled to nanogap metallic electrodes. The orbital quantization energies of the QDs and the tunnel resistances exhibited a strong dependence on growth temperature, TG, due to In–Ga intermixing during QD formation. When the intermixing was suppressed by reducing TG to 470 °C, the electron wave functions in the QDs become more extended in space and QD-electrode coupling sufficiently strong to form the Kondo singlet states at 4.3 K was realized even in a small QD of ∼45 nm diameter.


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