Planar and van der Waals heterostructures for vertical tunnelling single electron transistors

TL;DR

This paper demonstrates the fabrication of vertical single electron tunnelling transistors using combined in-plane and van der Waals heterostructures, specifically integrating graphene quantum dots within hexagonal boron nitride to improve device reproducibility and control.

Contribution

It introduces a novel approach of combining in-plane and van der Waals heterostructures for single electron transistors, utilizing hexagonal boron nitride barriers to enhance reproducibility.

Findings

Reduced localized states along quantum dot perimeters

Reproducible transistors using hexagonal boron nitride barriers

Enhanced device design flexibility

Abstract

Despite a rich choice of two-dimensional materials, which exists these days, heterostructures, both vertical (van der Waals) and in-plane, offer an unprecedented control over the properties and functionalities of the resulted structures. Thus, planar heterostructures allow p-n junctions between different two-dimensional semiconductors and graphene nanoribbons with well-defined edges; and vertical heterostructures resulted in the observation of superconductivity in purely carbon-based systems and realisation of vertical tunnelling transistors. Here we demonstrate simultaneous use of in-plane and van der Waals heterostructures to build vertical single electron tunnelling transistors. We grow graphene quantum dots inside the matrix of hexagonal boron nitride, which allows a dramatic reduction of the number of localised states along the perimeter of the quantum dots. The use of hexagonal boron nitride tunnel barriers as contacts to the graphene quantum dots make our transistors reproducible and not dependent on the localised states, opening even larger flexibility when designing future devices.