title: Quality evaluation of ultra-thin samples: Application to graphene.
abstract: Many new materials emerging are strictly two dimensional (2D), often only one or two monolayers thick. They include transition metal dichalcogenides, such as MoS2, and graphene. Graphene in particular appears to have many potential applications. Typically the crystalline film without contamination is of interest. Therefore, a reliable method is needed to routinely evaluate the quality of the synthesized samples. Here, we present one such candidate method that utilizes standard electron diffraction and low/medium magnification imaging in a rudimentary transmission electron microscope. The electron irradiation dose is very low thus reducing electron irradiation damage of the investigated samples. As an example, the method was applied to the evaluation of as-grown graphene sample quality and a study on heating-induced change in graphene. It can be used to evaluate the volume and areal ratio of crystalline to noncrystalline component. The method is amiable to automated film quality evaluation.
authors.affiliation: National Research Council Canada, National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, T6G 2M9, Canada.
authors.forename: K
authors.identifier: http://orcid.org/0000-0002-9349-9749
authors.initials: K
authors.lastname: Cui
authors.affiliation: National Research Council Canada, National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, T6G 2M9, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Bosnick
authors.affiliation: National Research Council Canada, National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, T6G 2M9, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Indoe
authors.affiliation: National Research Council Canada, National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, T6G 2M9, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Malac
authors.affiliation: Center for Cellular Imaging and NanoAnalytics, Universität Basel, Mattenstrasse 26, Basel, 4058, Switzerland.
authors.forename: R A
authors.initials: RA
authors.lastname: Mcleod
keywords: 2D film quality evaluation; electron diffraction; low dose imaging; radiation damage