We have grown site- and size-controlled InAs quantum dots (QDs) in shallow nanoholes prepared by using atomic force microscope (AFM)-assisted anodic nano-oxidation and subsequent etching, and investigated their transport properties by depositing metal nanogap electrodes on a single QD. We have observed clear diamond-like patterns in Coulomb stability diagrams, indicating that the fabricated single QD transistors operate as single electron transistors and that the site-controlled QDs have a good crystalline quality. Furthermore, we show that the charging energies and the orbital quantization energies can be controlled over a wide range by controlling the size of the QDs.

References

• K. M. Cha, K. Shibata, and K. Hirakawa: “Single electron transport through site-controlled InAs quantum dots”, Applied Physics Letters, 101, 223115-1~5, (2012); DOI: 10.1063/1.4769039.
• K. M. Cha, I. Horiuchi, K. Shibata, and K. Hirakawa： “Size-limiting effect of site-controlled InAs quantum dots grown at high temperatures by molecular beam epitaxy”, Applied Physics Express 5, pp. 085501-1 ~3, (2012); DOI:10.1143/APEX.5.085501.