Fabrication and characterization of physically-defined double quantum dots without unintentional localized states on highly-doped silicon substrate

We fabricated double quantum dots (DQDs) and a single electron transistor (SET) as a charge sensor (CS) on highly-doped silicon-on-insulator (SOI) substrate. We observed Coulomb oscillations, and Coulomb diamonds in the SET, and estimated its charging energy to be ∼15meV. We detected the change in the number of electrons of the DQDs with the CS, and observed a honeycomb-like charge stability diagram which is typical characteristics for DQDs. The regular shape of the charge stability diagram indicates that we succeeded in fabricating the DQDs without unintentional localized states.