Single Ge quantum dot placement along with self-aligned electrodes for effective management of single electron tunneling

We demonstrate controlled number and placement of the Ge quantum dot (QD) along with tunnel junction engineering through a self-organized approach for effective management of single electron tunneling. In this approach, a single Ge QD (~11 nm) self-aligning with nickel-silicide electrodes is realized by thermally oxidizing a SiGe nanorod bridging a 15-nm-wide nanotrench in close proximity to electrodes via a spacer bi-layer of Si₃N₄/SiO₂. The fabricated Ge QD single electron transistor exhibits clear Coulomb staircase and Coulomb diamond behaviors at T = 120-300 K.