Edge conductivity in PtSe$_2$ nanostructures
Roman Kempt Agnieszka Kuc Thomas Brumme Thomas Heine
PtSe$_2$ is a promising 2D material for nanoelectromechanical sensing and
photodetection in the infrared regime. One of its most compelling features is
the facile synthesis at temperatures below 500 {\deg}C, which is compatible
with current back-end-of-line semiconductor processing. However, this process
generates polycrystalline thin films with nanoflake-like domains of 5 to 100 nm
size. To investigate the lateral quantum confinement effect in this size
regime, we train a deep neural network to obtain an interatomic potential at
DFT accuracy and use that to model ribbons, surfaces, nanoflakes, and
nanoplatelets of PtSe$_2$ with lateral widths between 5 to 15 nm. We determine
which edge terminations are the most stable and find evidence that the
electrical conductivity is localized on the edges for lateral sizes below 10
nm. This suggests that the transport channels in thin films of PtSe$_2$ might
be dominated by networks of edges, instead of transport through the layers
themselves.