The composition and structure of the ubiquitous hydrocarbon contamination on van der Waals materials
A. Pálinkás, G. Kálvin, P. Vancsó, K. Kandrai, M. Szendrő, G. Németh, M. Németh, Á. Pekker, J.S. Pap, P. Petrik, K. Kamarás, L. Tapasztó, P. Nemes-Incze
Nature Communications 13 6770/1-10 oldal
The behavior of single layer van derWaals (vdW) materials is profoundly
influenced by the immediate atomic environment at their surface, a prime
example being the myriad of emergent properties in artificial heterostructures.
Equally significant are adsorbates deposited onto their surface
from ambient. While vdW interfaces are well understood, our knowledge
regarding atmospheric contamination is severely limited. Here we show that
the common ambient contamination on the surface of: graphene, graphite,
hBN and MoS2 is composed of a self-organized molecular layer, which forms
during a few days of ambient exposure. Using low-temperature STM measurements
we image the atomic structure of this adlayer and in combination
with infrared spectroscopy identify the contaminant molecules as normal
alkanes with lengths of 20-26 carbon atoms. Through its ability to self-organize,
the alkane layer displaces the manifold other airborne contaminant
species, capping the surface of vdW materials and possibly dominating their
interaction with the environment.
Submitted by: Kamarás Katalin, 24-11-2022 09:43, Type of article: Paper, Viewed: 407 times