title: Element discrimination in a hexagonal boron nitride nanosheet by aberration corrected transmission electron microscopy.
abstract: Boron nitride nanosheets prepared by an exfoliation technique were observed by aberration corrected transmission electron microscopy at 300 kV acceleration voltage. Single boron and nitrogen atoms in a monolayer region were imaged with different image contrast; a boron atom gave 16% less intensity reduction than a nitrogen atom. The number of atoms at each hexagonal ring site was determined by the image intensity that changed discretely with a 0.25-0.30 intensity difference. A double BN sheet was found to have a boron vacancy layer, and a triple BN layer has also a boron deficient layer on the incident surface resulting from the electron beam thinning process. The high sensitivity for atomic species was achieved by the high resolution and a small information limit due to the use of a cold field emission electron source.
authors.affiliation: International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan. MITOME.Masanori@nims.go.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Mitome
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Sawada
authors.forename: Yukihito
authors.initials: Y
authors.lastname: Kondo
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Tanishiro
authors.forename: Kunio
authors.initials: K
authors.lastname: Takayanagi