Fig. 1: Stripe patterns on vdW materials, due to ambient contamination.
From: The composition and structure of the ubiquitous hydrocarbon contamination on van der Waals materials
a PeakForce QNM topography maps measured on the surface of bulk HOPG, hBN, and MoS2 crystal terraces showing parallel stripes (Scale bars: 30 nm). b Room-temperature STM topography showing the smectic phase of the monolayer (Scale bar: 20 nm). c Low-temperature (9 K) STM topography map showing the inner structure of the stripes: the single molecular building blocks and the superlattice along the stripes. (Scale bar: 10 nm). Inset: 6 × 6 nm STM topography image showing the atomic scale structure of a molecular stripe. Single-molecule is shown by the red rectangle. d Schematic representation of the linear alkane molecules on a graphene surface. In all images, light blue arrows are parallel to the direction of the stripes, identified by AFM.
