Single-charge tunnelling in n- and p-type strained silicon germanium on silicon-on-insulator

Abstract

Dual-gate quantum dot transistors have been fabricated in n- and p-type strained SiGe on silicon-on-insulator. In single-gate modes, the narrow and wide gates on opposing sides modulate the single-charge tunnelling events in the quantum dot. When both gates are coupled together, the resultant modulation implies that capacitive coupling via the substrate controls the tunnelling. The coupling causes constructive-destructive effects in lifting-restoring the Coulomb blockade condition in the SiGe quantum dots.