Volume 13 Issue 12, December 2014

Three independent groups report the growth of two-dimensional heteromaterials with seamless vertical or lateral interfaces. The one-layer-thick transition metal dichalcogenides thus form heterojunctions with built-in device function.

High electrical contact resistance had stalled the promised performance of two-dimensional layered devices. Low-resistance metal–semiconductor contacts are now obtained by interfacing semiconducting MoS₂ layers with the metallic phase of this material.

Analysis of the growth patterns of calcitic prisms within the shell of the fan mollusc Pinna nobilis shows that growth can be predicted using grain theory and that the organic casings of the prisms set the thermodynamic boundaries.

By carefully selecting only two elemental 'building block materials' at the nanoscale, it is possible to digitally design composite electromagnetic media with properties vastly different from their individual constituents and suitable for performing complex optical functions.

Hexagonal boron nitride nanostructures are shown to sustain phonon–polariton modes with comparable performances to plasmon–polariton modes in graphene but with lower losses.

Two-dimensional electron gases forming at oxide interfaces and surfaces host a range of interesting properties. Photoelectron spectroscopy measurements now reveal a very large spin splitting of the surface electronic states of SrTiO₃.

Transition metal dichalcogenides are attracting widespread attention for their appealing optoelectronic properties. Using a combination of numerical and experimental techniques, the exciton binding energy is now determined for MoSe₂ on graphene.

Physical vapour transport is now used to grow single-atomic-layer lateral MoSe₂/WSe₂ heterojunctions, enabling the development of in-plane architectures for optoelectronic applications based on these semiconducting materials.

The morphology and mesostructure of the prismatic layer of a growing mollusc shell is observed by means of high-resolution synchrotron-based tomography and is shown to be fully predicted by classical theories of normal grain growth.

Deformable synthetic microgel particles bearing molecular-recognition motifs for fibrin fibres are shown to augment clotting in vitro and mimic in vivo clot contraction, thus recapitulating the functions of natural platelets.

Inspired by Boolean binary algebra, an approach to design electromagnetic metamaterials with desired permittivity by using just two elemental building blocks is demonstrated analytically and numerically.

The electronic band structure in silicon optical fibres can be engineered by continuous laser irradiation during the crystallization of the fibres. A reduction of the bandgap down to 0.59 eV is demonstrated.

Non-optimal electrical contacts can significantly limit the performance of MoS₂-based thin-film transistors. Transformation of semiconducting MoS₂ into its metallic phase is now shown as a viable strategy to decrease the metal–MoS₂ contact resistance.

Vapour growth of WS₂/MoS₂ two-dimensional materials at low and high temperature allows the synthesis of in-plane lateral heterojunctions and vertically stacked bilayers, respectively, with atomically sharp interfaces.

In situ electron energy-loss spectroscopy in an environmental transmission electron microscope reveals that palladium nanocrystals undergo sharp phase transitions during hydrogen absorption and desorption, and that surface effects dictate the size dependence of the hydrogen absorption pressures.

Investigation of the individual state-of-charge of particles in the phase-separating battery electrode lithium iron phosphate reveals that the fraction of active particles is highly dependent on cycle rate and direction. The findings could lead to enhanced current uniformity and cycle life in other electrode systems.

An adipocyte-targeting gene-carrier complex is shown to selectively transfect mature adipocytes by binding to the protein prohibitin and to lead to the metabolic recovery and to more than 20% body-weight reduction in obese mice.

Vigorous research on graphene and its applications has created a fertile ground for the investigation of a broad range of alternative two-dimensional materials. In this focus issue we take a closer look at the recent advances in the synthesis of layered transition metal dichalcogenides and in the understanding of their optoelectronic properties.

While power generation using silicon solar panels has steadily been increasing over the years, alternative materials that could compete with this technology in terms of efficiency and module costs are intensely being investigated. Yet, to allow for a fair assessment of new photovoltaic technologies, characterization of light-conversion performance should be conducted according to commonly agreed basic rules. This joint web focus collects a series of opinion pieces, recently published in Nature Materials,Nature NanotechnologyandNature Photonics, that discuss the importance of reporting accurate device performance.