SearcharxivSearch

arXiv subjects

Alexander S. Filatov

Publications and source records attributed to Alexander S. Filatov.

3 recordsLinked to original sources

Remote epitaxy beyond polarity

Remote epitaxy through a monolayer two-dimensional material-covered substrate establishes a crystallographic registry across the van der Waals (vdW) surface that enables the epitaxial growth, lift-off and transfer of single-crystalline films. A central belief in remote epitaxy is that the substrate facilitating the phenomenon must be a material with strong ionicity, as the interatomic electrostatic potential fluctuation in covalent and metallic materials is substantially attenuated by two-dimensional materials. Here, we show remote epitaxy is possible when the substrate is a metallic or covalently bonded material and experimentally demonstrate non-polar remote homo- and heteroepitaxy across a wide range of material systems, including both metals and semiconductors. The achieved non-polar remote interactions are designed and engineered by harnessing substrate conductivity and vicinal surface step-edge density. These findings indicate that remote epitaxy is universal and applicable to ionic, metallic, and covalent materials, expanding its capabilities and stimulating a plethora of new fundamental scientific questions about the mechanism of remote epitaxy.

cond-mat.mtrl-sci

Hybrid organic-inorganic two-dimensional metal carbide MXenes with amido- and imido-terminated surfaces

Two-dimensional (2D) transition-metal carbides and nitrides (MXenes) show impressive performance in applications, such as supercapacitors, batteries, electromagnetic interference shielding, or electrocatalysis. These materials combine the electronic and mechanical properties of 2D inorganic crystals with chemically modifiable surfaces, and surface-engineered MXenes represent an ideal platform for fundamental and applied studies of interfaces in 2D functional materials. A natural step in structural engineering of MXene compounds is the development and understanding of MXenes with various organic functional groups covalently bound to inorganic 2D sheets. Such hybrid structures have the potential to unite the tailorability of organic molecules with the unique electronic properties of inorganic 2D solids. Here, we introduce a new family of hybrid MXenes (h-MXenes) with amido- and imido-bonding between organic and inorganic parts. The description of h-MXene structure requires an intricate mix of concepts from the fields of coordination chemistry, self-assembled monolayers (SAMs) and surface science. The optical properties of h-MXenes reveal coherent coupling between the organic and inorganic components. h-MXenes also show superior stability against hydrolysis in aqueous solutions.

cond-mat.mtrl-sci

Direct synthesis and chemical vapor deposition of 2D carbide and nitride MXenes

Two-dimensional (2D) transition metal carbides and nitrides (MXenes) are a large family of materials actively studied for various applications, especially in the field of energy storage. To date, MXenes are commonly synthesized by etching the layered ternary compounds, MAX phases. Here we demonstrate a direct synthetic route for scalable and atom-economic synthesis of MXenes, including phases that have not been synthesized from MAX phases, by the reactions of metals and metal halides with graphite, methane or nitrogen. These directly synthesized MXenes showed excellent energy storage capacity for Li-ion intercalation. The direct synthesis enables chemical vapor deposition (CVD) growth of MXene carpets and complex spherulite-like morphologies. The latter form in a process resembling the evolution of cellular membranes during endocytosis.

cond-mat.mtrl-sci