Correction: Discovering atomistic pathways for supply of metal atoms from methyl-based precursors to graphene surface.

Correction for 'Discovering atomistic pathways for supply of metal atoms from methyl-based precursors to graphene surface' by Davide G. Sangiovanni et al., Phys. Chem. Chem. Phys., 2023, 25, 829-837, https://doi.org/10.1039/D2CP04091C.

A perspective on thermal stability and mechanical properties of 2D Indium Bismide fromab initiomolecular dynamics.

Identification and synthesis of 2D topological insulators is particularly elusive. According to previousab initiopredictions 2D InBi (Indium Bismide) is a material exhibiting topological properties which are combined with a band gap suitable for practical applications. We employab initiomolecular dynamics (AIMD) simulations to assess the thermal stability as well as the mechanical properties such as elastic modulus and stress-strain curves of 2D InBi. The obtained new knowledge adds further characteristics appealing to the feasibility of its synthesis and its potential applications. We find that pristine 2D InBi, H-InBi (hydrogenated 2D InBi) as well as 2D InBi heterostructures with graphene are all stable well above room temperature, being the calculated thermal stability for pristine 2D InBi 850 K and for H-InBi in the range above 500 K. The heterostructures of 2D InBi with graphene exhibit thermal stability exceeding 1000 K. In terms of mechanical properties, pristine 2D InBi exhibits similarities with another 2D material, stanene. The fracture stress for 2D InBi is estimated to be ∼3.3 GPa (∼3.6 GPa for stanene) while elastic modulus of 2D InBi reads ∼34 GPa (to compare with ∼23 GPa for stanene). Overall, the thermal stability, elastic, and fracture resistant properties of 2D InBi and its heterostructures with graphene appear as high enough to motivate future attempts directed to its synthesis and characterization.

Discovering atomistic pathways for supply of metal atoms from methyl-based precursors to graphene surface.

Conceptual 2D group III nitrides and oxides (e.g., 2D InN and 2D InO) in heterostructures with graphene have been realized by metal-organic chemical vapor deposition (MOCVD). MOCVD is expected to bring forth the same impact in the advancement of 2D semiconductor materials as in the fabrication of established semiconductor materials and device heterostructures. MOCVD employs metal-organic precursors such as trimethyl-indium, -gallium, and -aluminum, with (strong) metal-carbon bonds. Mechanisms that regulate MOCVD processes at the atomic scale are largely unknown. Here, we employ density-functional molecular dynamics - accounting for van der Waals interactions - to identify the reaction pathways responsible for dissociation of the trimethylindium (TMIn) precursor in the gas phase as well as on top-layer and zero-layer graphene. The simulations reveal how collisions with hydrogen molecules, intramolecular or surface-mediated proton transfer, and direct TMIn/graphene reactions assist TMIn transformations, which ultimately enables delivery of In monomers or InH and CH3In admolecules, on graphene. This work provides knowledge for understanding the nucleation and intercalation mechanisms at the atomic scale and for carrying out epitaxial growth of 2D materials and graphene heterostructures.

On Decorating a Honeycomb AlN Monolayer with Hydrogen and Fluorine Atoms: Ab Initio and Experimental Aspects.

Mono- and few-layer hexagonal AlN (h-AlN) has emerged as an alternative "beyond graphene" and "beyond h-BN" 2D material, especially in the context of its verification in ultra-high vacuum Scanning Tunneling Microscopy and Molecular-beam Epitaxy (MBE) experiments. However, graphitic-like AlN has only been recently obtained using a scalable and semiconductor-technology-related synthesis techniques, such as metal-organic chemical vapor deposition (MOCVD), which involves a hydrogen-rich environment. Motivated by these recent experimental findings, in the present work, we carried out ab initio calculations to investigate the hydrogenation of h-AlN monolayers in a variety of functionalization configurations. We also investigated the fluorination of h-AlN monolayers in different decoration configurations. We find that a remarkable span of bandgap variation in h-AlN, from metallic properties to nar-row-bandgap semiconductor, and to wide-bandgap semiconductor can be achieved by its hy-drogenation and fluorination. Exciting application prospects may also arise from the findings that H and F decoration of h-AlN can render some such configurations magnetic. We complemented this modelling picture by disclosing a viable experimental strategy for the fluorination of h-AlN.

Indium Nitride at the 2D Limit.

The properties of 2D InN are predicted to substantially differ from the bulk crystal. The predicted appealing properties relate to strong in- and out-of-plane excitons, high electron mobility, efficient strain engineering of their electronic and optical properties, and strong application potential in gas sensing. Until now, the realization of 2D InN remained elusive. In this work, the formation of 2D InN and measurements of its bandgap are reported. Bilayer InN is formed between graphene and SiC by an intercalation process in metal-organic chemical vapor deposition (MOCVD). The thickness uniformity of the intercalated structure is investigated by conductive atomic force microscopy (C-AFM) and the structural properties by atomic resolution transmission electron microscopy (TEM). The coverage of the SiC surface is very high, above 90%, and a major part of the intercalated structure is represented by two sub-layers of indium (In) bonded to nitrogen (N). Scanning tunneling spectroscopy (STS) measurements give a bandgap value of 2 ± 0.1 eV for the 2D InN. The stabilization of 2D InN with a pragmatic wide bandgap and high lateral uniformity of intercalation is demonstrated.

Optical properties of organosilicon compounds containing sigma-electron delocalization by quasiparticle self-consistent GW calculations.

We investigate theoretically the electronic and optical absorption properties of two sub-classes of oligosilanes: (i) Si(CH3)4, Si4(CH3)8, and Si8(CH3)8 that contain Si dot, ring and cage, respectively, and exhibit typical SiC and SiSi bonds; and (ii) persilastaffanes Si7H6(CH3)6 and Si12H6(CH3)12, which contain extended delocalized σ-electrons in SiSi bonds over three-dimensional Si frameworks. Our modeling is performed within the GW approach up to the partially self-consistent GW0 approximation, which is more adequate for reliably predicting the optical band gaps of materials. We examine how the optical properties of these organosilicon compounds depend on their size, geometric features, and Si/C composition. Our results indicate that the present methodology offers a viable way of describing the optical excitations of tailored functional Si-C-based clusters and molecular optical tags with potential use as efficient light absorbers/emitters in molecular optical devices.

Nanoscale phenomena ruling deposition and intercalation of AlN at the graphene/SiC interface.

The possibility for kinetic stabilization of prospective 2D AlN was explored by rationalizing metal organic chemical vapor deposition (MOCVD) processes of AlN on epitaxial graphene. From the wide range of temperatures which can be covered in the same MOCVD reactor, the deposition was performed at the selected temperatures of 700, 900, and 1240 °C. The characterization of the structures by atomic force microscopy, electron microscopy and Raman spectroscopy revealed a broad range of surface nucleation and intercalation phenomena. These phenomena included the abundant formation of nucleation sites on graphene, the fragmentation of the graphene layers which accelerated with the deposition temperature, the delivery of excess precursor-derived carbon adatoms to the surface, as well as intercalation of sub-layers of aluminum atoms at the graphene/SiC interface. The conceptual understanding of these nanoscale phenomena was supported by our previous comprehensive ab initio molecular dynamics (AIMD) simulations of the surface reaction of trimethylaluminum, (CH3)3Al, precursor with graphene. A case of applying trimethylindium, (CH3)3In, precursor to epitaxial graphene was considered in a comparative way.