Cleaning graphene: comparing heat treatments in air and in vacuum

Abstract

Surface impurities and contamination often seriously degrade the properties of two-dimensional materials such as graphene. To remove contamination, thermal annealing is commonly used. We present a comparative analysis of annealing treatments in air and in vacuum, both ex situ and "pre-situ", where an ultra-high vacuum treatment chamber is directly connected to an aberration-corrected scanning transmission electron microscope. While ex situ treatments do remove contamination, it is challenging to obtain atomically clean surfaces after ambient transfer. However, pre-situ cleaning with radiative or laser heating appears reliable and well suited to clean graphene without undue damage to its structure.

5 pages, 4 figures

References in corpus (5)

• Electric Field Effect in Atomically Thin Carbon Films
• Detection of Individual Gas Molecules Absorbed on Graphene
• Macroscopic graphene membranes and their extraordinary stiffness
• Manipulating low-dimensional materials down to the level of single atoms with electron irradiation
• Single-atom spectroscopy of phosphorus dopants implanted into graphene

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