Boron Nitride

Researchers from Shanghai Jiao Tong University and Shanghai Electric Power Generation Equipment have developed a multilayer graphene-based thermally conductive and electrically insulating tape (MTCEIT) that achieves a combination of lateral heat spreading capability and dielectric integrity for compact, high-power electronic systems. 

The continuous miniaturization of integrated devices, accompanied by exponentially increasing power densities, imposes stringent requirements on thermal interface materials (TIMs) that must efficiently dissipate heat while providing strong electrical insulation within submillimeter thickness constraints. Conventional polymer composites and ceramic-filled films struggle to meet these competing demands, typically exhibiting in-plane thermal conductivities below 70 W m⁻¹ K⁻¹ once their thickness exceeds 200 µm. To overcome this limitation, the MTCEIT integrates graphene paper - a stacked and compressed assembly of two-dimensional graphene sheets - as a high-efficiency lateral heat spreading layer. 

Researchers from the Beijing Institute of Technology, Peking University and Japan's National Institute for Materials Science have developed a few-layer graphene/CrOCl/few-layer graphene van der Waals (vdW) heterostructure that functions as a broadband infrared optoelectronic synaptic device, notable for its tunable spike timing-dependent plasticity and a broad spectral response range of 520–2000 nanometers. This system addresses the limitations of conventional 2D synaptic devices, which are typically restricted to visible light due to their material bandgaps.

The device is composed of two thin graphene layers separated by a chromium oxychloride (CrOCl) barrier, all encapsulated in hexagonal boron nitride for stability. When a voltage is applied, electrons tunnel through the CrOCl layer, even in the absence of light—a behavior distinct from metal-contact devices. Upon illumination (including infrared wavelengths), interfacial coupling drives charge transfer from graphene to CrOCl, modulating the tunneling barrier and triggering synaptic plasticity effects, such as spike-number and frequency-dependent plasticity.

A research team, led by Daniil Gorbachev and Na Xin at the University of Manchester and working with colleagues including Kenji Watanabe and Takashi Taniguchi, demonstrated a major improvement in graphene’s electronic properties by strategically positioning graphite gates in extremely close proximity to the material. 

This innovative approach, which involves placing the gates just one nanometer away, dramatically reduces charge variations and potential fluctuations, ultimately boosting graphene’s mobility to exceed even the highest-quality semiconductor heterostructures. The resulting material exhibits exceptional performance, enabling the observation of subtle quantum phenomena previously hidden by disorder and paving the way for a new era in two-dimensional materials research.

Researchers from Yale University, California Institute of Technology, City University of New York, Kansas State University and ETH Zurich have reported a new way of generating long-wave infrared and terahertz waves. The work could pave the way towards cheaper, smaller long-wave infrared light sources and more efficient device cooling.

Phonon-polaritons are a unique type of electromagnetic wave that occurs when light interacts with vibrations in a material's crystal lattice structure. These phonon-polariton waves exhibit several unique characteristics. For example, they can concentrate the energy of long-wavelength infrared light into extremely small volumes, even down to tens of nanometers, as well as effectively move heat away from the source. This makes phonon-polaritons ideal for high-tech applications like sub-wavelength imaging, molecular sensors, and heat management within electronics. However, research on phonon-polariton waves has thus far mainly focused on fundamental studies in laboratory settings, with practical device applications remaining largely unexplored.

A University of Manchester team of scientists has reported a 'significant milestone in the field of quantum electronics' with their latest study on spin injection to graphene. The paper outlines advancements in spintronics and quantum transport.

Spin transport electronics, or spintronics, represents a revolutionary alternative to traditional electronics by utilizing the spin of electrons rather than their charge to transfer and store information. This method promises energy-efficient and high-speed solutions that exceed the limitations of classical computation, for next generation classical and quantum computation. The Manchester team, led by Dr. Ivan Vera-Marun, has fully encapsulated monolayer graphene in hexagonal boron nitride, an insulating and atomically flat 2D material, to protect its high quality. By engineering the 2D material stack to expose only the edges of graphene, and laying magnetic nanowire electrodes over the stack, they successfully form one-dimensional (1D) contacts.

A collaborative effort involving POSTECH and the University of Technology Sydney has yielded an advancement in light source technology. The team used graphene to develop a quantum light emitting diode (Quantum LED) that can precisely emit light using a single atom. This innovative technology generates light by injecting charges into a luminescent material composed of a single atom. 

The research team implemented this advanced light source technology using hexagonal boron nitride (hBN), a material known for its ability to stably confine electrons in various atomic defects. Unlike traditional quantum dots, which are composed of hundreds to thousands of atoms, the quantum LED developed by the team exhibits excellent quantum light source characteristics even at room temperature. This breakthrough addresses a significant challenge in the field, as hBN's wide bandgap has historically made it difficult to inject charges electrically, thus hindering the development of LED devices. To overcome this obstacle, the researchers designed a "graphene-hBN-graphene" van der Waals tunneling structure. 

Researchers at Korea's Pohang University of Science and Technology and Japan's National Institute for Materials Science have developed a way to control the properties of graphene by combining superconductors and graphene. 

Professor Lee Gil-ho of Pohang University of Science and Technology (POSTECH) and researchers from the Research Institute, in collaboration with Kenji Watanabe and Takashi Taniguchi from the National Institute for Materials Science (NIMS) in Japan, noted they have successfully improved the junction characteristics between graphene and superconducting electrodes. 

Researchers at Florida State University (FSU), Chinese Academy of Sciences (CAS) and Wuhan University have examined how physical manipulations of graphene, such as layering and twisting, impact its optical properties and conductivity. 

The team, led by Assistant Professor Guangxin Ni, along with Assistant Professor Cyprian Lewandowski and graduate research assistant Ty Wilson, found that the conductivity of twisted bilayer graphene is not heavily impacted by physical or chemical manipulations and instead depends more on how the material’s minute geometry structure changes by interlayer twisting — a revelation that opens the door for additional studies on how lower temperatures and frequencies impact graphene’s properties.

Polaritons are coupled excitations of electromagnetic waves with either charged particles or vibrations in the atomic lattice of a given material. One of their most attractive properties is the capacity to confine light at the nanoscale, which is even more extreme in two-dimensional (2D) materials. 2D polaritons have been investigated by optical measurements using an external photodetector. However, their effective spectrally resolved electrical detection via far-field excitation remains unexplored. This hinders their exploitation in crucial applications such as sensing, hyperspectral imaging, and optical spectrometry, banking on their potential for integration with silicon technologies. 

Recently, researchers from Spain's ICFO, the University of Ioannina, Universidade do Minho, the International Iberian Nanotechnology Laboratory, Kansas State University, the National Institute for Materials Science (Tsukba, Japan), POLIMA (University of Southern Denmark) and URCI (Institute of Materials Science and Computing, have reported on the electrical spectroscopy of polaritonic nanoresonators based on a high-quality 2D-material heterostructure, which serves at the same time as the photodetector and the polaritonic platform. Subsequently, the team electrically detected these mid-infrared resonators by near-field coupling to a graphene pn-junction. The nanoresonators simultaneously exhibited extreme lateral confinement and high-quality factors. 

NTT Corporation, along with The University of Tokyo and National Institute for Materials Science (NIMS), showed that graphene plasmon wave packets can be generated, manipulated and read out on-chip using terahertz electronics.  

The team managed to electrically generate and control graphene plasmon wave packets with a pulse width of 1.2 picoseconds. This result shows that the phase and amplitude of a terahertz signal can be controlled electrically by using graphene plasmons. It enables terahertz signal processing, a method different from conventional electrical circuit technology using transistors and is expected to contribute to realizing ultrahigh-speed signal processing in the future.