Atomic-Scale Structural and Chemical Characterization of Hexagonal Boron Nitride Layers Synthesized at the Wafer-Scale with Monolayer Thickness Control

Wei Hsiang Lin, Victor W. Brar, Deep Jariwala, Michelle C. Sherrott, Wei Shiuan Tseng, Chih I. Wu, Nai Chang Yeh, Harry A. Atwater*

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Hexagonal boron nitride (h-BN) is a promising two-dimensional insulator with a large band gap and low density of charged impurities that is isostructural and isoelectronic with graphene. Here we report the chemical and atomic-scale structure of CVD-grown wafer-scale (∼25 cm2) h-BN sheets ranging in thickness from 1 to 20 monolayers. Atomic-scale images of h-BN on Au and graphene/Au substrates obtained by scanning tunneling microscopy reveal high h-BN crystalline quality in monolayer samples. Further characterization of 1-20 monolayer samples indicates uniform thickness for wafer-scale areas; this thickness control is a result of precise control of the precursor flow rate, deposition temperature and pressure. Raman and infrared spectroscopy indicate the presence of B-N bonds and reveal a linear dependence of thickness with growth time. X-ray photoelectron spectroscopy shows the film stoichiometry, and the B/N atom ratio in our films is 1 ± 0.6% across the range of thicknesses. Electrical current transport in metal/insulator/metal (Au/h-BN/Au) heterostructures indicates that our CVD-grown h-BN films can act as excellent tunnel barriers with a high hard-breakdown field strength. Our results suggest that large-area h-BN films are structurally, chemically and electronically uniform over the wafer scale, opening the door to pervasive application as a dielectric in layered nanoelectronic and nanophotonic heterostructures.

Original languageEnglish
Pages (from-to)4700-4707
Number of pages8
JournalChemistry of Materials
Volume29
Issue number11
DOIs
StatePublished - 13 Jun 2017

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