Definition
Plain language
A single one-atom-thick layer of a material.
As stated in the literature
A single atomic-thickness layer of a layered crystal (graphene, hBN, transition metal dichalcogenides), distinguished from bilayer or bulk by characteristic optical contrast.
Also called: monolayers
Why it matters: Monolayers exhibit electronic and optical properties absent in the bulk material, which is the whole point of 2D-materials research.
For example, a single sheet of graphene one carbon atom thick is the monolayer form of graphite.
Heard on the show
“… "exfoliate a chip," which is move stage, position tape, press, hold, peel; "search the chip for monolayer flakes," which involves a scan pattern, image capture, and segmentation. …”Episode 072 — A Robot Made Graphene Without Help, And Caught Itself Hallucinating