We use laterally coupled two self-assembled quantum dots (QDs) to study the effect of asymmetric coupling to the source and drain electrodes. From the measured stability diagram, we confirm that one QD (Dot 1 ) is tunnel-coupled to the two electrodes, whereas the other (Dot 2) is only tunnel-coupled to one electrode. We observe the asymmetric current-voltage characteristics, when Dot 2 acts as an electron trap only for one bias polarity to impede the electron flow through Dot 1 due to the inter-dot Coulomb coupling. This phenomenon can be understood within the scheme of charge ratchet effect.
ASJC Scopus subject areas
- Physics and Astronomy(all)