Boron Nitride - Page 5

Researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have designed a graphene device that switches from a superconducting material to an insulator and back again to a superconductor — all with a flip of a switch. The team shared that the device exhibits this unique versatility while being thinner than a human hair.

Views of the trilayer graphene/boron nitride heterostructure device as seen through an optical microscope. The gold, nanofabricated electric contacts are shown in yellow; the silicon dioxide/silicon substrate is shown in brown and the boron nitride flakes

"Usually, when someone wants to study how electrons interact with each other in a superconducting quantum phase versus an insulating phase, they would need to look at different materials. With our system, you can study both the superconductivity phase and the insulating phase in one place," said Guorui Chen, the study's lead author and a postdoctoral researcher in the lab of Feng Wang, who led the study. Wang, a faculty scientist in Berkeley Lab's Materials Sciences Division, is also a UC Berkeley physics professor.

Researchers at the University of Cambridge and Jiangnan University in China have developed graphene-enhanced wearable electronic components incorporated directly into fabrics. The devices could be used for flexible circuits, healthcare monitoring, energy conversion, and other applications.

The researchers have shown how graphene and other related materials can be directly incorporated into fabrics to produce charge storage elements such as capacitors, paving the way to textile-based power supplies which are washable, flexible and comfortable to wear.

Scientists from Manchester University, the Ulsan National Institute of Science & Technology and the Korea Institute of Science and Technology have developed a novel technology, which combines the fabrication procedures of planar and vertical heterostructures in order to assemble graphene-based single-electron transistors.

The schematic structure of the devices

In the study, it was demonstrated that high-quality graphene quantum dots (GQDs), regardless of whether they were ordered or randomly distributed, could be successfully synthesized in a matrix of monolayer hexagonal boron nitride (hBN). Here, the growth of GQDs within the layer of hBN was shown to be catalytically supported by the platinum (Pt) nanoparticles distributed in-between the hBN and supporting oxidised silicon (SiO₂) wafer, when the whole structure was treated by the heat in the methane gas (CH₄). It was also shown, that due to the same lattice structure (hexagonal) and small lattice mismatch (~1.5%) of graphene and hBN, graphene islands grow in the hBN with passivated edge states, thereby giving rise to the formation of defect-less quantum dots embedded in the hBN monolayer.

Graphene and 2D materials producer Grolltex has announced the completion of its recent capacity expansion and released production for 30,000 eight-inch wafer equivalents per year at its CVD monolayer fabrication facility in San Diego, California.

This is the only commercial CVD monolayer graphene production facility in California and in fact it is the largest capacity plant of its kind in the U.S., said CEO, Jeff Draa. Demand for our electronics grade graphene has never been better. Our production lines are capable of producing single layer graphene or single layer hexagonal Boron Nitride.

Graphene Flagship researchers at DTU, Denmark, solved the problem of graphene's accumulation of defects and impurities due to environmental exposure by protecting it with insulating layers of hexagonal boron nitride, another two-dimensional material with insulating properties.

Peter Bøggild, researcher at Graphene Flagship partner DTU and coauthor of the paper, explains that although 'graphene is a fantastic material that could play a crucial role in making new nano-sized electronics, it is still extremely difficult to control its electrical properties.' Since 2010, scientists at DTU have tried to tailor the electrical properties of graphene, by making a very fine pattern of holes, so that channels through which an electric power can flow freely are formed. 'Creating nanostructured graphene turned out to be amazingly difficult, since even small errors wash out all the properties we designed it to have,' comments Bøggild.

A new study led by the Ulsan National Institute of Science and Technology in South Korea reveals a technology capable of fabricating highly ordered arrays of graphene quantum dots.

Graphene quantum dots of various sizes in a stable, ordered array

The research team demonstrated a novel way of synthesizing GQDs, embedded inside a hexagonal boron nitride (hBN) matrix. Thus, they demonstrated simultaneous use of in-plane and van der Waals heterostructures to build vertical single-electron tunneling transistors.

Rice University and Iran University of Science and Technology researchers have found a unique ceramic material that could act as a sensor for structures.

The ceramic becomes more electrically conductive under elastic strain and less conductive under plastic strain, and could lead to a new generation of sensors embedded into structures like buildings, bridges and aircraft able to monitor their own health.

Graphene Flagship researchers produced graphene-based spintronics devices that utilize both electron charge and spin at room temperature. Demonstrating the spin’s feasibility for bridging distances of up to several micrometres, these results may open the door to new possibilities for integrating information-processing and storage in a single chip.

The Graphene Flagship program recognizes the potential of spintronics devices made from graphene-related materials. Researchers from different universities successfully showed that it is possible to manipulate graphene’s spin properties in a controlled manner at room temperature. These results inspire new directions in the development of spin-logic devices and quantum computing. With miniaturization a major driving force behind the electronics industry, graphene opens new possibilities for compacting spin-logic operations with magnetic memory elements in a single platform, notes Catalan Institution for Research and Advanced Studies (ICREA) Research Professor Stephan Roche, who has been leading the Graphene Flagships Spintronics Work Package since its inception.

A team of researchers from Russia, UK, Japan and Italy has created a graphene-based terahertz detector.

The team explains that the reason for the inefficiency of existing terahertz detectors is the mismatch between the size of the detecting element, the transistor—about one-millionth of a meter—and the typical wavelength of terahertz radiation, which is about 100 times greater. This results in the wave passing the detector by without any interaction.

A team of researchers from Denmark, Italy and Portugal recently discovered a new mechanism for controlling electronic devices using molecules. The researchers have shown that the ferroelectric ordering of polar molecules attached to the edge of graphene can be toggle-switched by an electrostatic gate and can be used for memory devices and sensors.

Molecular electronics aims to use individual molecules to control electronics. The large library of molecules and techniques to modify them can create more sophisticated electronics than previously thought possible. The normal hindrance is the small size of the molecules. It's possible to create them, but they are incredibly difficult to handle. It is almost impossible to manipulate small enough features in ordinary materials to electrically connect with individual molecules.