Fig. 4: Self-assembled alkane layer as the source of friction domains.
From: The composition and structure of the ubiquitous hydrocarbon contamination on van der Waals materials
a PF topography image of a tripoint boundary of the stripes on graphene on hBN sample. b Contact mode torsion signal on the same area as (a), revealing three distinct friction domains corresponding to the three differently oriented molecule domains. (Scale bars on a and b: 100 nm). c Intentionally drawn nested, square-shaped friction domains generated by fast scanning parallel to the three zigzag directions of the substrate (pink arrows). The blue dotted line represents a zigzag-terminated edge of the thick (70 nm) hBN crystal on SiO2, while pink and green arrows show the fast and slow scanning directions of the preceding drawing steps (Scale bar: 10 μm).
