title: Structural and Electrical Investigation of C60-Graphene Vertical Heterostructures.
abstract: Graphene, with its unique electronic and structural qualities, has become an important playground for studying adsorption and assembly of various materials including organic molecules. Moreover, organic/graphene vertical structures assembled by van der Waals interaction have potential for multifunctional device applications. Here, we investigate structural and electrical properties of vertical heterostructures composed of C60 thin film on graphene. The assembled film structure of C60 on graphene is investigated using transmission electron microscopy, which reveals a uniform morphology of C60 film on graphene with a grain size as large as 500 nm. The strong epitaxial relations between C60 crystal and graphene lattice directions are found, and van der Waals ab initio calculations support the observed phenomena. Moreover, using C60-graphene heterostructures, we fabricate vertical graphene transistors incorporating n-type organic semiconducting materials with an on/off ratio above 3 × 10(3). Our work demonstrates that graphene can serve as an excellent substrate for assembly of molecules, and attained organic/graphene heterostructures have great potential for electronics applications.
authors.affiliation: ‡Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea.
authors.forename: Kwanpyo
authors.initials: K
authors.lastname: Kim
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Lee
authors.affiliation: #School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom.|∧School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast BT9 5AL, United Kingdom.
authors.forename: Elton J G
authors.initials: EJ
authors.lastname: Santos
authors.forename: Pil Sung
authors.initials: PS
authors.lastname: Jo
authors.forename: Alberto
authors.initials: A
authors.lastname: Salleo
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Nishi
authors.forename: Zhenan
authors.initials: Z
authors.lastname: Bao
keywords: C60; graphene; organic semiconducting molecules; vertical heterostructures; vertical transistors