Formation of quantum dot in graphene single nanoconstriction

Abstract

We report the experimental and theoretical investigation of single carrier transport property on graphene single-constriction devices. As the Fermi wavelength is comparable with the width of the constriction and shorter than the length of the constriction in our device, the single quantum dot-dominated characteristic is observed by back-gate modulation. The first-principles calculation shows that discrete states are induced in the narrower constriction due to the mode mixing in the narrower constriction and wider leads. It is found that the geometry of constriction-wider lead junctions plays a crucial role in single-dot formation in graphene constriction structure.

Fabrication and characterization of quantum dot devices based on tetralayer graphene/hexagonal boron nitride heterostructures

“…These features indicate that the multiple Coulomb islands coupled in series and parallel contribute the transport characteristics, 33) resulting in a stochastic Coulomb blockade. 34) Such multiple dots behavior was commonly observed in the nanostructure graphene QD 2,3,7) and graphene nanoribbon devices, [35][36][37][38][39][40] mainly caused by edge disorder and potential inhomogeneity. The multiple dot behavior in our device can be attributed to the edge disorder rather than the potential inhomogeneity, because the hBNencapsulation prevents the 4LG from the influence of charged impurities.…”