Synthesis of In-Plane Artificial Lattices of Monolayer Multijunctions.

Recently, monolayers of van der Waals materials, including transition metal dichalcogenides (TMDs), are considered ideal building blocks for constructing 2D artificial lattices and heterostructures. Heterostructures with multijunctions of more than two monolayer TMDs are intriguing for exploring new physics and materials properties. Obtaining in-plane heterojunctions of monolayer TMDs with atomically sharp interfaces is very significant for fundamental research and applications.

Autocatalytic surface reduction and its role in controlling seed-mediated growth of colloidal metal nanocrystals.

The growth of colloidal metal nanocrystals typically involves an autocatalytic process, in which the salt precursor adsorbs onto the surface of a growing nanocrystal, followed by chemical reduction to atoms for their incorporation into the nanocrystal. Despite its universal role in the synthesis of colloidal nanocrystals, it is still poorly understood and controlled in terms of kinetics. Through the use of well-defined nanocrystals as seeds, including those with different types of facets, sizes, and internal twin structure, here we quantitatively analyze the kinetics of autocatalytic surface reduction in an effort to control the evolution of nanocrystals into predictable shapes.

Toward a Quantitative Understanding of the Reduction Pathways of a Salt Precursor in the Synthesis of Metal Nanocrystals.

Despite the pivotal role played by the reduction of a salt precursor in the synthesis of metal nanocrystals, it is still unclear how the precursor is reduced. The precursor can be reduced to an atom in the solution phase, followed by its deposition onto the surface of a growing nanocrystal. Alternatively, the precursor can adsorb onto the surface of a growing nanocrystal, followed by reduction through an autocatalytic process.

Phase-driven magneto-electrical characteristics of single-layer MoS2.

Magnetism of the MoS2 semiconducting atomic layer was highlighted for its great potential in the applications of spintronics and valleytronics. In this study, we demonstrate an evolution of magneto-electrical properties of single layer MoS2 with the modulation of defect configurations and formation of a partial 1T phase. With Ar treatment, sulfur was depleted within the MoS2 flake leading to a 2H (low-spin) → partial 1T (high-spin) phase transition.

Extremely high efficient nanoreactor with Au@ZnO catalyst for photocatalysis.

We fabricated a photocatalytic Au@ZnO@PC (polycarbonate) nanoreactor composed of monolayered Au nanoparticles chemisorbed on conformal ZnO nanochannel arrays within the PC membrane. A commercial PC membrane was used as the template for deposition of a ZnO shell into the pores by atomic layer deposition (ALD). Thioctic acid (TA) with sufficient steric stabilization was used as a molecular linker for functionalization of Au nanoparticles in a diameter of 10 nm.

Synthesis and characterization of one-dimensional Ag-doped ZnO/Ga-doped ZnO coaxial nanostructure diodes.

In the pursuit of high injection current diode nanodevices, entire one-dimensional (1D) ZnO coaxial nanostructures with p-n homojunctions is one of the ideal structures. In this study, we synthesized entire 1D ZnO-based coaxial homojunction diodes with p-type Ag-doped ZnO (SZO) nanostructure shells covering n-type Ga-doped ZnO (GZO) nanopagoda (NPG) cores by a metal-organic chemical vapor deposition (MOCVD) technique. The entire 1D SZO-GZO and SZO-ZnO coaxial nanostructures exhibit better diode characteristics, such as lower threshold voltage, better rectification ratios, and better ideality factor n, than that reported for either 2D or 2D-1D p-n heterojunction and/or homojunction diodes.

High density unaggregated Au nanoparticles on ZnO nanorod arrays function as efficient and recyclable photocatalysts for environmental purification.

Photodegradation of organic pollutants in aqueous solution is a promising method for environmental purification. Photocatalysts capable of promoting this reaction are often composed of noble metal nanoparticles deposited on a semiconductor. Unfortunately, the separation of these semiconductor-metal nanopowders from the treated water is very difficult and energy consumptive, so their usefulness in practical applications is limited.

Prominent electric properties of BiFeO₃ shells sputtered on ZnO-nanorod cores with LaNiO₃ buffer layers.

In this work, template-assisted methods were adopted to grow BiFeO3 (BFO)-nanorod arrays on substrates. Well-aligned ZnO-nanorod arrays (ZNAs) grown hydrothermally were chosen as positive templates. It was found that perovskite BFO could not be radio frequency (RF)-magnetron sputtered directly on a ZNA at elevated temperatures.

Synthesis of BiFeO3/ZnO core-shell hetero-structures using ZnO nanorod positive templates.

We report the synthesis, morphology, and magnetization characteristics of BiFeO(3) (BFO)-covered ZnO nanorod arrays (ZNAs). High quality and well-aligned ZNAs were grown by a hydrothermal method. BFO shells were deposited by sputtering at ambient temperature and then annealing in an oxygen atmosphere.