page_title: Two-dimensional materials
section_title: Metals
hierarchical_section_title: Two-dimensional materials / 2D allotropes / Metals
caption_attribution_description: English: 3D AFM tomography images of multilayered Palladium nanosheet on silicon wafer.
context_page_description: Two-dimensional materials, sometimes referred to as single-layer materials, are crystalline materials consisting of a single layer of atoms. These materials have found use in applications such as photovoltaics, semiconductors, electrodes and water purification.
  2D materials can generally be categorised as either 2D allotropes of various elements or as compounds. The elemental 2D materials generally carry the -ene suffix in their names while the compounds have -ane or -ide suffixes. Layered combinations of different 2D materials are generally called van der Waals heterostructures.
  The efficient integration of 2D functional layers with three-dimensional systems remains a significant challenge, limiting device performance and circuit design.
  Some 700 2D materials have been predicted to be stable, although many remain to be synthesized. The global market for 2D materials is expected to reach US$390 million by 2025, mostly for graphene in the semiconductor, electronics, battery energy and composite materials markets.
context_section_description: Single and double atom layers of platinum in a two-dimensional film geometry has been demonstrated. These atomically thin platinum films are epitaxially grown on graphene which imposes a compressive strain that modifies the surface chemistry of the platinum, while also allowing charge transfer through the graphene. Single atom layer of palladium with the thickness down to 2.6 Å, and rhodium with the thickness of less than 4 Å  have also been synthesized and characterized with atomic force microscopy and transmission electron microscopy.
caption: 3D AFM topography image of multilayered palladium nanosheet.[45]
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