posted on 2021-06-09, 19:47authored byAlberto Trentino, Jacob Madsen, Andreas Mittelberger, Clemens Mangler, Toma Susi, Kimmo Mustonen, Jani Kotakoski
Structural engineering
is the first step toward changing properties
of materials. While this can be at relative ease done for bulk materials,
for example, using ion irradiation, similar engineering of 2D materials
and other low-dimensional structures remains a challenge. The difficulties
range from the preparation of clean and uniform samples to the sensitivity
of these structures to the overwhelming task of sample-wide characterization
of the subjected modifications at the atomic scale. Here, we overcome
these issues using a near ultrahigh vacuum system comprised of an
aberration-corrected scanning transmission electron microscope and
setups for sample cleaning and manipulation, which are combined with
automated atomic-resolution imaging of large sample areas and a convolutional
neural network approach for image analysis. This allows us to create
and fully characterize atomically clean free-standing graphene with
a controlled defect distribution, thus providing the important first
step toward atomically tailored two-dimensional materials.