Graphene’s success has shown that it is possible to create stable, single and few-atom-thick layers of van der Waals materials, and also that these materials can exhibit fascinating and technologically useful properties. Here we review the state-of-the-art of 2D materials beyond graphene. Initially, we will outline the different chemical classes of 2D materials and discuss the various strategies to prepare single-layer, few-layer, and multilayer assembly materials in solution, on substrates, and on the wafer scale. Additionally, we present an experimental guide for identifying and characterizing single-layer-thick materials, as well as outlining emerging techniques that yield both local and global information. We describe the differences that occur in the electronic structure between the bulk and the single layer and discuss various methods of tuning their electronic properties by manipulating the surface. Finally, we highlight the properties and advantages of single-, few-, and many-layer 2D materials in...

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Progress, Challenges, and Opportunities in Two-Dimensional Materials Beyond Graphene

The discovery of uniform deposition of high-quality single layered graphene on copper has generated significant interest. That interest has been translated into rapid progress in terms of large area deposition of thin films via transfer onto plastic and glass substrates. The opto-electronic properties of the graphene thin films reveal that they are of very high quality with transmittance and conductance values of >90% and 30Ω/sq, both are comparable to the current state-of-the-art indium tin oxide transparent conductor. In this Feature Article, we provide a detailed and up to date description of the literature on the subject as well as highlighting challenges that must be overcome for the utilization of graphene deposited on copper substrates by chemical vapour deposition.

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A review of chemical vapour deposition of graphene on copper

Graphene on metal surfaces

Carbon nanofibers (sometimes known as carbon filaments) can be produced in a relative large scale by the catalytic decomposition of certain hydrocarbons on small metal particles. The diameter of the nanofibers is governed by that of the catalyst particles responsible for their growth. By careful manipulation of various parameters it is possible to generate carbon nanofibers in assorted conformations and at the same time also control the degree of their crystalline order. This paper is a review of the recent advances made in the development of these nanostructures, with emphasis both on the fundamental aspects surrounding the growth of the material and a discussion of the key factors which enable one to control their chemical and physical properties. Attention is also given to some of the possible applications of the nanostructures which center around the unique blend of properties exhibited by the material.

A review of catalytically grown carbon nanofibers

Graphene: Synthesis and applications

https://escholarship.org/content/qt62v5w069/qt62v5w069.pdf?t=p0jvrl

Surface Structures on the Clean Platinum (100) Surface

It is found for the first time that a molecule can induce a displacive reconstruction in the substrate on which it is adsorbed. This is observed in a refined structure determination of Rh(111)(2\ifmmode\times\else\texttimes\fi{}2)-${\mathrm{C}}_{2}$${\mathrm{H}}_{3}$, in which ${\mathrm{C}}_{2}$${\mathrm{H}}_{3}$ (ethylidyne) is adsorbed on the Rh(111) single-crystal surface. This result strengthens an earlier hypothesis that catalytic reactions are usually accompanied by distortions in the catalyst, which can profoundly affect reaction rates and selectivities.

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Molecule-induced displacive reconstruction in a substrate surface: Ethylidyne adsorbed on Rh(111) studied by low-energy-electron diffraction

https://escholarship.org/content/qt73n0m6wh/qt73n0m6wh.pdf?t=p0jube

Molecule-Induced Displacive Reconstruction in a Substrate Surface: Ethylidyne Adsorbed on Rh(111), Studied by Low-Energy Electron Diffraction

The intensity of specularly reflected [(00) reflection] low‐energy (5‐500‐eV) electrons has been measured as a function of temperature for the (100) and (111) faces of palladium and for the (111) face of lead in the temperature ranges 25°‐600°C and 25°‐225°C, respectively. From the data, the root‐mean‐square displacements, 〈u⊥〉, of surface atoms perpendicular to the surface planes and the surface Debye temperatures have been calculated. The mean vibrational amplitudes of surface atoms are 40%→100% larger than for bulk atoms. There is little difference between the surface mean displacements of different crystal orientations; 〈u⊥〉 appears to be relatively insensitive to changes of surface structure or surface density. The experimental results correlate well with those obtained for platinum and silver single‐crystal surfaces. It is believed that all monatomic face‐centered cubic crystal surfaces should have mean displacements markedly larger than those in the bulk.

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G. A. Somorjai

Papers

Surface Structures on the Clean Platinum (100) Surface

Molecule-induced displacive reconstruction in a substrate surface: Ethylidyne adsorbed on Rh(111) studied by low-energy-electron diffraction

Molecule-Induced Displacive Reconstruction in a Substrate Surface: Ethylidyne Adsorbed on Rh(111), Studied by Low-Energy Electron Diffraction

Mean Displacement of Surface Atoms in Palladium and Lead Single Crystals

Charge transfer controlled surface interactions between oxygen and CdSe films