Single Germanium Quantum-dot Placement Along With Self-Aligned Electrodes for Effective Management of Single Charge Tunneling

We demonstrated the controlled placement of a Ge quantum dot (QD) along with tunnel-junction engineering in a self-organized approach for the effective management of single charge tunneling. In this approach, a single-Ge-QD ( ~ 11 nm) self-aligning with nickel-polycide electrodes is realized by thermally oxidizing a SiGe nanorod that bridges a 15-nm-wide nanotrench in close proximity to electrodes via a spacer bilayer of Si₃N₄/SiO₂. The fabricated Ge-QD single-hole transistor exhibits clear Coulomb oscillation and Coulomb diamond behaviors at T = 77 K-150 K, providing a way to analyze the electronic structure of the Ge QD.