Two-dimensional layers of metal dichalcogenides have attracted much attention because of their ultrathin thickness and potential applications in electronics and optoelectronics. Monolayer SnS₂, with a band gap of ~2.6 eV, has an octahedral lattice made of two atomic layers of sulfur and one atomic layer of tin. Till date, there have been limited reports on the growth of large-scale and high quality SnS₂ atomic layers and the investigation of their properties as a semiconductor. Here, we report the chemical vapor deposition (CVD) growth of atomic-layer SnS₂ with a large crystal size and uniformity. In addition, the number of layers can be changed from a monolayer to few layers and to bulk by changing the growth time. Scanning transmission electron microscopy was used to analyze the atomic structure and demonstrate the 2H stacking poly-type of different layers. The resultant SnS₂ crystals is used as a photodetector with external quantum efficiency as high as 150%, suggesting promise for optoelectronic applications.

The thermal conduction of suspended few-layer hexagonal boron nitride (h-BN) sheets was experimentally investigated using a noncontact micro-Raman spectroscopy method. The first-order temperature coefficients for monolayer (1L), bilayer (2L) and nine-layer (9L) h-BN sheets were measured to be -(3.41 ± 0.12) × 10^-2, -(3.15 ± 0.14) × 10^-2 and -(3.78 ± 0.16) × 10^-2 cm^-1·K^-1, respectively. The room-temperature thermal conductivity of few-layer h-BN sheets was found to be in the range from 227 to 280 W·m^-1·K^-1, which is comparable to that of bulk h-BN, indicating their potential use as important components to solve heat dissipation problems in thermal management configurations.

Magnetic nanowires (NWs) are ideal materials for the fabrication of various multifunctional nanostructures which can be manipulated by an external magnetic field. Highly crystalline and textured nanowires of nickel (Ni NWs) and cobalt (Co NWs) with high aspect ratio (˜330) and high coercivity have been synthesized by electrodeposition using nickel sulphate hexahydrate (NiSO₄·6H₂O) and cobalt sulphate heptahydrate (CoSO₄·7H₂O) respectively on nanoporous alumina membranes. They exhibit a preferential growth along 〈110〉. A general mobility assisted growth mechanism for the formation of Ni and Co NWs is proposed. The role of the hydration layer on the resulting one-dimensional geometry in the case of potentiostatic electrodeposition is verified. A very high interwire interaction resulting from magnetostatic dipolar interactions between the nanowires is observed. An unusual low-temperature magnetisation switching for field parallel to the wire axis is evident from the peculiar high field M(T) curve.

Rapid progress in graphene-based applications is calling for new processing techniques for creating graphene components with different shapes, sizes, and edge structures. Here we report a controlled cutting process for graphene sheets, using nickel nanoparticles as a knife that cuts with nanoscale precision. The cutting proceeds via catalytic hydrogenation of the graphene lattice, and can generate graphene pieces with specific zigzag or armchair edges. The size of the nanoparticle dictates the edge structure that is produced during the cutting. The cutting occurs along straight lines and along symmetry lines, defined by angles of 60° or 120°, and is deflected at free edges or defects, allowing practical control of graphene nano-engineering.