Search

Among ultrathin monoelemental two-dimensional (2D) materials, bismuthene, the single layer of heavier group-VÎ' element bismuth (Bi), has been predicted to have large non trivial gap. Here, we demonstrate the growth of Bi films by molecular beam epitaxy on 2D-HfTe2 template. At the initial stage of Bi deposition (1â€"2 bilayers, BL), both the pseudocubic Bi(110) and the hexagonal Bi(111) phases are formed. When reaching 3 BL Bi, a transformation to pure hexagonal Bi(111) occurs. The electronic band structure of 3 BL Bi(111) films was measured by angle-resolved photoemission spectroscopy showing very good matching with the density functional theory band structure calculations of 3 BL free standing Bi(111). The grown Bi(111) thin film was capped with a protective Al2O3 layer and its stability under ambient conditions, necessary for practical applications and device fabrication, was confirmed by x-ray photoelectron spectroscopy and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

The synthesis of new Xenes and their potential applications prototypes have achieved significant milestones so far. However, to date the realization of Xene heterostructures in analogy with the well known van der Waals heterostructures remains an unresolved issue. Here, a Xene heterostructure concept based on the epitaxial combination of silicene and stanene on Ag(111) is introduced, and how one Xene layer enables another Xene layer of a different nature to grow on top is demonstrated. Single‐phase (4 × 4) silicene is synthesized using stanene as a template, and stanene is grown on top of silicene on the other way around. In both heterostructures, in situ and ex situ probes confirm layer‐by‐layer growth without intercalations and intermixing. Modeling via density functional theory shows that the atomic layers in the heterostructures are strongly interacting, and hexagonal symmetry conservation in each individual layer is sequence selective. The results provide a substantial step toward currently missing Xene heterostructures and may inspire new paths for atomic‐scale materials engineering. [ABSTRACT FROM AUTHOR]

• β -phase allotrope of Sb is synthetized by a new method based on MOCVD. • Thin Sb epitaxial nanocrystals are grown on Ge substrates by a Au-catalysed process. • Raman measurements and simulations indicate antimonene-like properties. • The new method can pave the way to large-area antimonene layers for novel devices. Synthetic two-dimensional (2D) mono-elemental crystals, namely X-enes, have recently emerged as a new frontier for atomically thin nanomaterials with on-demand properties. Among X-enes, antimonene, the β -phase allotrope of antimony, is formed by atoms arranged in buckled hexagonal rings bearing a comparatively higher environmental stability with respect to other players of this kind. However, the exploitation of monolayer or few-layer antimonene and other 2D materials in novel opto-electronic devices is still hurdled by the lack of scalable processes. Here, we demonstrated the viability of a bottom-up process for the epitaxial growth of antimonene-like nanocrystals (ANCs), based on a Metal-Organic Chemical Vapor Deposition (MOCVD) process, assisted by gold nanoparticles (Au NPs) on commensurate (1 1 1)-terminated Ge surfaces. The growth mechanism was investigated by large- and local-area microstructural analysis, revealing that the etching of germanium, catalyzed by the Au NPs, led to the ANCs growth on the exposed Ge (1 1 1) planes. As a supportive picture, ab-initio calculations rationalized this epitaxial relationship in terms of compressively strained β -phase ANCs. Our process could pave the way to the realization of large-area antimonene layers by a deposition process compatible with the current semiconductor manufacturing technology. [ABSTRACT FROM AUTHOR]

Isolation of graphene is today a milestone in condensed matter physics that paves the way to a new entire class of 2D synthetic materials referred to as Xenes with no analogous bulk layered allotropes. The booming rush to discover first novel and unprecedented materials flows into two generations of Xenes: the first one strictly relates to carbon being made of elements of the IV/14 column/group of the periodic table, and the second one includes elements of the adjacent columns. From borophene to tellurene, with rare exceptions, the physics and chemistry of the elements are rewritten and herein reviewed in terms of their fundamental and peculiar properties. Particular attention is paid to the epitaxial methodologies and configurational details, aiming at determining key points for nanotechnology applications of the Xenes afforded by scalability, quality, and stability aspects. Finally, the ongoing efforts to devise and realize applications based on the Xenes are summarized. [ABSTRACT FROM AUTHOR]