title: van der Waals Heterostructures with High Accuracy Rotational Alignment.
abstract: We describe the realization of van der Waals (vdW) heterostructures with accurate rotational alignment of individual layer crystal axes. We illustrate the approach by demonstrating a Bernal-stacked bilayer graphene formed using successive transfers of monolayer graphene flakes. The Raman spectra of this artificial bilayer graphene possess a wide 2D band, which is best fit by four Lorentzians, consistent with Bernal stacking. Scanning tunneling microscopy reveals no moiré pattern on the artificial bilayer graphene, and tunneling spectroscopy as a function of gate voltage reveals a constant density of states, also in agreement with Bernal stacking. In addition, electron transport probed in dual-gated samples reveals a band gap opening as a function of transverse electric field. To illustrate the applicability of this technique to realize vdW heterostructuctures in which the functionality is critically dependent on rotational alignment, we demonstrate resonant tunneling double bilayer graphene heterostructures separated by hexagonal boron-nitride dielectric.
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Kyounghwan
authors: K
authors: Kim
authors: Physics Department, University of Arizona , Tucson, Arizona 85721, United States.
authors: Matthew
authors: M
authors: Yankowitz
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Babak
authors: B
authors: Fallahazad
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Sangwoo
authors: S
authors: Kang
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Hema C P
authors: HC
authors: Movva
authors: Physics Department, University of Arizona , Tucson, Arizona 85721, United States.
authors: Shengqiang
authors: S
authors: Huang
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Stefano
authors: S
authors: Larentis
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Chris M
authors: CM
authors: Corbet
authors: National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan.
authors: Takashi
authors: T
authors: Taniguchi
authors: National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan.
authors: Kenji
authors: K
authors: Watanabe
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Sanjay K
authors: SK
authors: Banerjee
authors: Physics Department, University of Arizona , Tucson, Arizona 85721, United States.
authors: Brian J
authors: BJ
authors: LeRoy
authors: Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
authors: Emanuel
authors: E
authors: Tutuc
keywords: Two-dimensional; boron-nitride; graphene; heterostructure; resonant tunneling