SiC nanowires (NWs) designed from selected bulk polytypes are investigated using quantum mechanics-based simulations (both ab initio and semiempirical methods), and their structure–property relationships examined vis-à-vis their size, shape, and orientation. It is found that 2H–SiC NWs of hexagonal morphology oriented along the <0001> direction are the most stable ones compared to NWs designed using other bulk polytypes (e.g., 3C, 4H, or 6H) and other morphologies (round, square, rhombus, etc.) for diameters with 1 nm < d < 14 nm. Based on the electronic density calculations, it is found that 2H–SiC <0001> NWs exhibit semiconductor-like characteristics (akin to their bulk counterparts), even when their diameters approach 1 nm. On the other hand, SiC NWs designed from 3C, 4H, and 6H bulk polytypes, regardless of their morphology, exhibit gapless features for diameters less than 3.5 nm. Undoubtedly, these novel properties of SiC NWs can be exploited in the fabrication of nanoscale devices.

The phase evolution, nucleation, and sintered ceramics of barium titanate (BaTiO3, BT) powder prepared by solid-state synthesis with an ultrafine starting material (27 m2/g of BaCO3 and 190 m2/g of TiO2) were investigated in this study. Surface diffusion between BaCO3 and TiO2 was observed at a relatively low temperature of 400 °C by transmission electron microscopy. Rapid nucleation of the BT and cubic BT phases was observed at 500 °C by x-ray diffraction. The derivative thermogravimetry curve clearly shows a single step of BT formation at 600 °C. In short, pure BT particles with an average particle size of 250 nm and high tetragonality were prepared by solid-state synthesis, which produced X7R ceramics with high dielectric permittivity, high insulation resistance, and a clear core–shell structure.

The effect of the use of different zinc salts as zinc sources during hydrothermal growth of zinc oxide nanowires was systematically investigated. Change in the temperature, pH, and transmittance of the growth solutions prepared with three different zinc salts was monitored and used to provide a broad explanation to the effect of the salt. In addition to conventional heating process, microwave heating of the growth solutions was also performed, and differences in the ZnO nanowires synthesized through both heating methods were examined. It was found that ionization of zinc in growth solutions is influencing the formation of ZnO nanowires leading to growth with different aspect ratios, and zinc acetate dihydrate salt allows the synthesis of nanowires with the highest aspect ratio.

Electrons and photons can coexist as a single entity called a surface plasmon—an elementary excitation found at the interface between a conductor and an insulator. Because of their hybrid electric and photonic nature, plasmons allow photons to be precisely controlled on the nanoscale. Plasmons are evident in the vivid hues of rose windows, which derive their color from small metallic nanoparticles embedded in the glass. They also provide the basis for color-changing biosensors (such as home pregnancy tests), photothermal cancer treatments, improved photovoltaic cell efficiencies, and nanoscale lasers. While surface plasmons were first identified nearly 55 years ago, many of their exciting applications are yet to come. This issue of MRS Bulletin reviews the progress and promise of plasmonics—from the characterization tools that have allowed nanometer-scale probing of plasmons to the new materials that may enable low-loss, active, and quantum plasmonics. Within reach are applications ranging from integrated plasmonic circuits for nanophotonic computation to plasmonic optical tweezers for manipulation of nano-sized particles and proteins.

Plasmonic metal nanoparticles have the ability to act as nanoscale antennas for visible and near-IR (infrared) light, leading to increased electromagnetic fields at their surface. As a result, Raman scattering and/or fluorescence from nearby molecules can be enhanced by many orders of magnitude. However, imaging how these molecules interact with the enhanced fields at the surface of noble metal nanoparticles is a challenge due to the diffraction limit of light. In this article, we review super-resolution imaging of plasmonic hot spots using two all-optical readouts, surface-enhanced Raman scattering and surface-enhanced fluorescence, which are used to locate and track single or a few molecules on the surface of nanoscale-roughened metals. These super-resolution imaging techniques allow localization of the emission centroid of an emitter to better than 5 nm and allow mapping of the electromagnetic field enhancement experienced by molecules at the nanoparticle surface.

Plasmonics aims at combining features of photonics and electronics by coupling photons with a free-electron gas, whose subwavelength oscillations (surface plasmons) enable manipulation of light at the nanoscale and engender the exciting properties of optical metamaterials. Plasmonics is facing a grand challenge of overcoming metal losses impeding its progress. We reflect on the reasons why subwavelength confinement and loss are intimately intertwined and investigate the physics of loss in conductors beyond the conventional Drude model. We suggest that commonly used noble metals may not be the best materials for plasmonics and describe alternate materials such as transparent conducting oxides and transition metal nitrides. We consider the prospects of compensating the loss with gain materials and conclude that the so-far elusive solution to the loss obstacle lies in finding better materials with lower losses.