Towards the selective growth of two-dimensional ordered CN compounds via epitaxial substrate mediation.

Two-dimensional (2D) ordered carbon-nitrogen binary compounds (CN) show great potential in many fields owing to their diverse structures and outstanding properties. However, the scalable and selective synthesis of 2D CN compounds remain a challenge due to the variable C/N stoichiometry induced coexistence of graphitic, pyridinic, and pyrrolic N species and the competitive growth of graphene. Here, this work systematically explored the mechanism of selective growth of a series of 2D ordered CN compounds, namely, the g-CN, CN, CN, and CN, on various epitaxial substrates via first-principles calculations.

Mechanism of Controllable Growth of Large-Area Single-Crystal Hexagonal Boron Nitride on Preoxidized Copper Substrate.

Two-dimensional (2D) hexagonal boron nitride (-BN) exhibits promising properties for electronic and photoelectric devices, while the growth of high-quality -BN remains challenging. Here we theoretically explored the mechanism of epitaxial growth of high-quality -BN by using the preoxidized and hydrogen-annealed copper substrate, i.e.

Uniform nucleation and epitaxy of bilayer molybdenum disulfide on sapphire.

Two-dimensional transition-metal dichalcogenides (TMDs) are of interest for beyond-silicon electronics. It has been suggested that bilayer TMDs, which combine good electrostatic control, smaller bandgap and higher mobility than monolayers, could potentially provide improvements in the energy-delay product of transistors. However, despite advances in the growth of monolayer TMDs, the controlled epitaxial growth of multilayers remains a challenge.

The Intrinsic Thermodynamic Difficulty and a Step-Guided Mechanism for the Epitaxial Growth of Uniform Multilayer MoS with Controllable Thickness.

Multilayer MoS shows superior performance over the monolayer MoS for electronic devices while the growth of multilayer MoS with controllable and uniform thickness is still very challenging. It is revealed by calculations that monolayer MoS domains are thermodynamically much more favorable than multilayer ones on epitaxial substrates due to the competition between surface interactions and edge formation, leading accordingly to a layer-by-layer growth pattern and non-continuously distributed multilayer domains with uncontrollable thickness uniformity. The thermodynamics model also suggests that multilayer MoS domains with aligned edges can significantly reduce their free energy and represent a local minimum with very prominent energy advantage on a potential energy surface.

Molecular dynamics simulation on the reaction of nano-aluminum with water: size and passivation effects.

The reaction of aluminum and water is widely used in the field of propulsion and hydrogen production, but its reaction characteristics at the nanometer scale have not been fully studied. In this paper, the effect of particle size and surface passivation of aluminum particle on the reaction mechanism was studied by using reactive molecular dynamics (RMD) simulation. The reduction of aluminum particle size can accelerate the reaction rate in the medium term (20-80 ps) due to the increase of activity, but it also produces an agglomeration effect as the temperature increases.