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 MoS , 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.

Toward Quantitative Bright Field TEM Imaging of Ultra Thin Samples

“…The mass thickness values of graphene were slightly offset in horizontal direction for clarity. The amorphous carbon data were reproduced from[1].…”

“…Two dimensional (2D) materials, such as graphene and transition metal dichalcogenides, are of potential interest from both exploratory research and application perspectives. Here we discuss the potential of bright field transmission electron microscopy (BFTEM) for quantitative mass thickness mapping of ultra thin samples illustrated using graphene [1,2].…”