Direct writing of heterostructures in single atomically precise graphene nanoribbons

TL;DR

This paper demonstrates the atomic-scale fabrication of heterostructures within graphene nanoribbons using STM, revealing their electronic properties and potential for nanoelectronic device applications.

Contribution

It introduces a novel method for directly writing heterostructures in graphene nanoribbons with atomic precision using STM manipulation.

Findings

Heterostructures exhibit type-I band alignment.

Quantum confinement and orbital hybridization observed.

Potential for creating double barrier quantum dot structures.

Abstract

Precision control of interfacial structures and electronic properties is the key to the realization of functional heterostructures. Here, utilizing the scanning tunneling microscope (STM) both as a manipulation and characterization tool, we demonstrate the fabrication of a heterostructure in a single atomically precise graphene nanoribbon (GNR) and report its electronic properties. The heterostructure is made of a seven-carbon-wide armchair GNR and a lower band gap intermediate ribbon synthesized bottom-up from a molecular precursor on an Au substrate. The short GNR segments are directly written in the ribbon with an STM tip to form atomic precision intraribbon heterostructures. Based on STM studies combined with density functional theory calculations, we show that the heterostructure has a type-I band alignment, with manifestations of quantum confinement and orbital hybridization. Our finding demonstrates a feasible strategy to create a double barrier quantum dot structure with atomic precision for novel functionalities, such as negative differential resistance devices in GNR-based nanoelectronics.