Double quantum dot-like transport in controllably doped graphene nanoribbon

Abstract

In this Letter, we demonstrate coupled double-quantum dot (DQD)-like transport in an ∼ 30 nm-wide controllably doped graphene nanoribbon (GNR). Controlled doping is introduced from hydrogen silsesquioxane by changing its electron exposure dose. The proximity effect, which brings in additional dose accumulation, is utilized to introduce two charge puddles with stronger p-doping at the two ends of the moderately p-doped GNR, which act as two quantum dots. By electrostatically isolating these two charge puddles with simplified overlapping dual gates, DQD-like transport features are measured in the doped GNR at a temperature of 5 K. Moreover, the transition from strongly to weakly coupled DQDs is observed due to electrically tunable inter-dot coupling.