title: Postsynthesis of h-BN/Graphene Heterostructures Inside a STEM.
abstract: Combinations of 2D materials with different physical properties can form heterostructures with modified electrical, mechanical, magnetic, and optical properties. The direct observation of a lateral heterostructure synthesis is reported by epitaxial in-plane graphene growth from the step-edge of hexagonal BN (h-BN) within a scanning transmission electron microscope chamber. Residual hydrocarbon in the chamber is the carbon source. The growth interface between h-BN and graphene is atomically identified as largely N-C bonds. This postgrowth method can form graphene nanoribbons connecting two h-BN domains with different twisting angles, as well as isolated carbon islands with arbitrary shapes embedded in the h-BN layer. The electronic properties of the vertically stacked h-BN/graphene heterostructures are investigated by electron energy-loss spectroscopy (EELS). Low-loss EELS analysis of the dielectric response suggests a robust coupling effect between the graphene and h-BN layers.
authors.affiliation: Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, Orsay, 91405, France.
authors.forename: Luiz H G
authors.initials: LH
authors.lastname: Tizei
authors.affiliation: Division of Electron Crystallography and Spectroscopy, Tohoku University, Sendai, 980-8577, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan.
authors.forename: Yung-Chang
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan.
authors.forename: Chao-Hui
authors.initials: CH
authors.lastname: Yeh
authors.affiliation: Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan.
authors.forename: Po-Wen
authors.initials: PW
authors.lastname: Chiu
authors.affiliation: Division of Electron Crystallography and Spectroscopy, Tohoku University, Sendai, 980-8577, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Terauchi
authors.affiliation: Meijo University, Department of Materials Science and Engeering, Nagoya, 468-8502, Japan.
authors.forename: Sumio
authors.initials: S
authors.lastname: Iijima
authors.affiliation: Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan.
authors.forename: Kazu
authors.initials: K
authors.lastname: Suenaga
keywords: EELS; STEM; graphene; h-BN; heterostructures