Cleaning graphene

Subtitle:Comparing heat treatments in air and in vacuum
Authors/others:Tripathi, Mukesh; Mittelberger, Andreas; Mustonen, Kimmo; Mangler, Clemens; Kotakoski, Jani; Meyer, Jannik C.; Susi, Toma

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 damage to most suspended areas. Pre situ annealing of typical dirty graphene samples yields atomically clean areas several hundred nm2 in size.

Number of pages:5
Date of publication:8.2017
Journal title:Physica Status Solidi. Rapid Research Letters
Peer reviewed:true
Digital Object Identifier (DOI):
Publication Type:Article