Showing Spotlights 33 - 40 of 303 in category All (newest first):
Many 2D materials with atomic-scale thicknesses suffer from oxidation and degradation effects under ambient conditions, which is one of the biggest obstacles in their practical applications. A 75-month study used atomic force microscopy to investigate the long-term evolution of oxidative defects on transition metal dichalcogenides (TMDs). Intriguingly, the researchers found that long-term storage in ambient conditions led to evolution of a distinct ring-like pattern resembling the tree-lines arising from seasonal changes.
Nov 22nd, 2021
Precise patterning of 2D materials is a route to computation and storage using 2D materials, which can deliver potentially better performance and much lower power consumption compared to the technology of today. Researchers now demonstrate an etching process that makes it possible to downsize nanostructures to the 10-20 nm range and obtain smooth edges, sharp corners, and feature sizes significantly below the resolution limit of electron beam lithography. The nanostructured 2D materials can be used themselves or as etch masks to pattern other nanomaterials.
Sep 4th, 2021
Negative differential resistance (NDR), which describes a decrease in electrical current as the applied bias increases, has always been one of the hottest topics in solid-state electronic devices since L. Esaki first demonstrated this phenomenon in heavily-doped Ge p-n junctions in 1958. Researchers now report the modulation of a unique room-temperature NDR effect with high peak current in ambipolar black phosphorus transistors. The simplicity of this structure, combined with the recent progress in scalable production of BP films, makes the BP NDR devices promising for practical electronic applications.
Aug 10th, 2021
Photodetectors with blackbody response show significant applications in remote sensing and infrared imaging. However, up to now, few works have demonstrated excellent response to blackbody radiation (weak irregular radiation from a real object), which is essential to reliably evaluate their potential in practical detections. Researchers now have demonstrated van der Waals unipolar barrier photodetectors with nBn and pBp heterostructures. Designing unipolar barriers with conventional materials is challenging due to the strict requirements of lattice and band matching.
Jun 24th, 2021
For the enormous promises of graphene and other two-dimensional (2D) materials to be fulfilled, scientists need a much better understanding of how specific types of defects in the crystal structure, including those that change location over time, affect its properties. To do that, they first need to identify the location and type of defect and then be able to precisely alter the structure of 2D materials in order to tailor their properties for applications based on them. Addressing this issue, researchers now have demonstrated structural engineering and atomic-scale analysis of graphene up to a level that so far has not been possible.
Jun 17th, 2021
MXenes move nanotechnology from using a few 'wonder materials' to manipulation of hundreds and even thousands of 2D building blocks to assemble designer materials and devices. Those materials can contribute to solving the key problems in the fields of energy (generation, harvesting, storage), water (desalination, purification), food (longer storage, sensing of degradation/bacteria), environment (clean air and water) and medicine (treatment, diagnostics, artificial organs).
Jun 16th, 2021
In general, there are three types of driving force for ion transport: electric field; mechanical pressure; and concentration gradient. Recently, light has been propsoed as a fourth. Now, researchers report the incorporation of a transition metal dichalcogenides based van der Waals multilayer heterostructure into nanofluidic materials, and demonstrate a new photo-induced active ion transport phenomenon. This will inspire a broad range of fundamental research and practical application for light-controlled ionic circuits, artificial photosynthesis, biomimetic energy conversion, and so on.
Mar 4th, 2021
In order to exploit the remarkable mechanical properties of graphene for practical applications, nanoscale graphene sheets need to be assembled into much larger, macroscopic structures. However, there are two pivotal issues that make this task challenging: One is the inherently misaligned and wrinkled structure of graphene platelets; another is the weak interfacial interaction among graphene platelets. Both these problems greatly degrade the properties of macroscopic graphene assemblies such as sheets and fibers.
Feb 10th, 2021