Researchers report a highly efficient graphene/hBN-based electro-absorption modulator

ICFO researchers led by Professor Frank Koppens, in collaboration with researchers from Universita di Pisa, CNIT, Ghent University-IMEC, and NIMS, have reported a novel electro-absorption (EA) modulator capable of showing a 3-fold increase in static and dynamic modulation efficiency while maintaining the high-speed, a value that surpasses those for previously reported graphene EA modulators.

 Electrical connections and schematic cross-section of an EA modulator with an hBN–HfO2–hBN dielectric image

To achieve this, the team of researchers developed a high-quality graphene-based electro-absorption modulator by combining high-quality graphene and a high-k dielectric, also used in microelectronics. The high quality of the graphene was achieved by integrating it with the 2d-material dielectric hexagonal boron nitride (hBN).

Scientists discover important new property of graphene

MIT researchers and colleagues have discovered a new and important electronic property of graphene. The work, which involves structures composed of atomically thin layers of materials that are also biocompatible, could usher in new, faster information-processing paradigms. One potential application is in neuromorphic computing, which aims to replicate the neuronal cells in the body responsible for everything from behavior to memories.

“Graphene-based heterostructures continue to produce fascinating surprises. Our observation of unconventional ferroelectricity in this simple and ultra-thin system challenges many of the prevailing assumptions about ferroelectric systems and it may pave the way for an entire generation of new ferroelectrics materials,” says Pablo Jarillo-Herrero, the Cecil and Ida Green Professor of Physics at MIT and leader of the work, which involved a collaboration with five other MIT faculty from three departments.

AIXTRON's new graphene and hBN industrial grade reactor goes into operation

AIXTRONAixtron logo has developed, built and installed a new, specific industrial grade reactor for graphene and hexagonal Boron Nitride (hBN) processing on 200 mm epi-wafers. The new CVD tool was developed as part of the GIMMIK research project and has recently gone into operation.

The GIMMIK project aims to evaluate the production of graphene layers under industrial conditions, spotting weak points and designing ways of eliminating the sources of error. Furthermore, the transfer of the properties of graphene to electrical components by integration into a material environment are to be tested. In parallel, methods for the large-area, contact-free characterization of graphene will be developed, which do not yet exist at present. The GIMMIK research project aims to expand graphene technology for electronic components and to bring it up to a production-relevant level. Participants of the GIMMIK project include: AIXTRON SE, Infineon Technologies, IHP GmbH - Leibniz-Institut für innovative Mikroelektronik, Protemics, LayTec, RWTH Aachen.

Researchers achieve direct visualization of of quantum dots in bilayer graphene

Researchers at UC Santa Cruz have reported the first direct visualization of quantum dots in bilayer graphene, revealing the shape of the quantum wave function of the trapped electrons. The finding of this research could provide important fundamental knowledge, required for developing quantum information technologies based on bilayer graphene quantum dots.

Direct visualization of quantum dots reveals shape of quantum wave function imageImage from Nano Letters

"There has been a lot of work to develop this system for quantum information science, but we've been missing an understanding of what the electrons look like in these quantum dots," said corresponding author Jairo Velasco Jr., assistant professor of physics at UC Santa Cruz.

University of Manchester team discovers a new family of quasiparticles in graphene-based superlattices

Researchers at The University of Manchester, led by Sir Andre Geim and Dr Alexey Berdyugin, have discovered and characterized a new family of quasiparticles named 'Brown-Zak fermions' in graphene-based superlattices. This was achieved by aligning the atomic lattice of a graphene layer to that of an insulating boron nitride sheet, dramatically changing the properties of the graphene sheet.

The study follows years of successive advances in graphene-boron nitride superlattices which has previously allowed the observation of a fractal pattern known as the Hofstadter's butterfly - and now, with this current work, the researchers report another highly surprising behavior of particles in such structures under applied magnetic field.