Electronics

Graphene’ s quantum properties, such as superconductivity and other unique quantum behaviors, are known to arise when graphene atomic layers are stacked and twisted with precision to produce “ABC stacking domains.” Historically, achieving ABC stacking domains required exfoliating graphene and manually twisting and aligning layers with exact orientations—an intricate process that is difficult to scale for industrial applications.

Recently, researchers at NYU Tandon School of Engineering and Charles University in Prague, led by Elisa Riedo and Herman F. Mark, uncovered a new phenomenon in graphene research, observing growth-induced self-organized ABA and ABC stacking domains that could promote the development of advanced quantum technologies. The findings of their study demonstrate how specific stacking arrangements in three-layer epitaxial graphene systems emerge naturally — eliminating the need for complex, non-scalable techniques traditionally used in graphene twisting fabrication.

 A semiconductor startup called Destination 2D has announced it has successfully achieved wafer-scale synthesis of high-quality graphene within CMOS-compatible process conditions. In doing so, the company is enabling the use of graphene as a 2D material in mainstream semiconductor products through its 300mm scale graphene synthesis equipment – the CoolC GT300™.

The issues facing the semiconductor industry as they relate to interconnects are profoundly impacted by the ever-shrinking dimensions of regular process technology. The standard interconnect material, copper, has been used for the past 30 years and is now reaching commercial end-of-life due to Moore’s Law and electron migration that renders copper extremely problematic in low geometry fabrication. At sub-15 nm interconnect dimensions, the resistivity of copper increases rapidly – causing significant degradation in both circuit and system-level performance, power, and dramatically impacting all reliability metrics required by modern semiconductor designs in products such as GPUs, CPUs and others.

Researchers from North Carolina State University and Iowa State University have demonstrated a new technique for self-assembling electronic devices. The proof-of-concept work was used to create diodes and transistors, and could pave the way for self-assembling more complex electronic devices without relying on existing computer chip manufacturing techniques.

D-Met fabricated patterns produce components for potential use in microelectromechanical systems (MEMS). Image credit: Julia Chang and NCSU.

“Existing chip manufacturing techniques involve many steps and rely on extremely complex technologies, making the process costly and time consuming,” says Martin Thuo, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University. “Our self-assembling approach is significantly faster and less expensive. We’ve also demonstrated that we can use the process to tune the bandgap for semiconductor materials and to make the materials responsive to light – meaning this technique can be used to create optoelectronic devices. What’s more, current manufacturing techniques have low yield, meaning they produce a relatively large number of faulty chips that can’t be used. Our approach is high yield – meaning you get more consistent production of arrays and less waste.”

Israeli-based 2D Generation (2DG), which specializes in graphene-based solutions for semiconductors, has been acquired by ASX-listed Adisyn (ASX:AI1), a provider of tech services for SMEs in the Australian defense sector that has expanded its focus to the semiconductor industry through this acquisition.

Adisyn is also one of the founders of Connecting Chips European Union Joint Undertaking, a collaboration that includes industry leaders like NVIDIA, Valeo, and Applied Materials. This acquisition not only brings Adisyn cutting-edge technology, but potentially opens the door for the company to enter the semiconductor space.

Researchers at the Technical University of Liberec (Czech Republic) and Lodz University of Technology (Poland) have developed a silver/graphene flexible composite electrode using inkjet printing technology for high-performance supercapacitors. 

The scientists chose rGO as the primary material for the electrode active layer. The rGO active layer was in-situ printed and reduced on the polypropylene non-woven fabric, and silver nanoparticles were simultaneously inserted and reduced to increase the interlayer spacing of the rGO active layer, which effectively reduced the self-stacking effect of rGO and improved the overall electrochemical performance. 

Researchers from Queen Mary University of London and Paragraf Limited have reported a 'significant step forward in the development of graphene-based memristors' for potential use in future computing systems and artificial intelligence (AI). 

This innovation, which has been achieved at wafer scale, begins to pave the way toward scalable production of graphene-based memristors, devices crucial for non-volatile memory and artificial neural networks (ANNs). Memristors are recognized as potential game-changers in computing, offering the ability to perform analogue computations, store data without power, and mimic the synaptic functions of the human brain. The integration of graphene can enhance these devices dramatically, but has been notoriously difficult to incorporate into electronics in a scalable way until recently. 

While silk protein has been used in designer electronics, its use is currently limited in part because silk fibers are a messy tangle of spaghetti-like strands. To address this, researchers from Pacific Northwest National Laboratory, University of Washington, Lawrence Berkeley National Laboratory, North Carolina State University and Xiamen University have developed a uniform two-dimensional (2D) layer of silk protein fragments, or "fibroins," on graphene. 

Scheme of silk fibroin assembly on highly oriented pyrolytic graphite (HOPG) characterized by in situ AFM. Image from Science Advances

The scientists explained that their work provides a reproducible method for silk protein self-assembly that is essential for designing and fabricating silk-based electronics. They said that the system is nontoxic and water-based, which is vital for biocompatibility.

Researchers from Advanced Material Development (AMD) and the University of Sussex have announced what they refer to as "a major enhancement" in their carbon nanomaterial-based inks, reaching conductivity levels of 3,000,000 Sm-¹, approaching the performance of incumbent metal-based solutions.

With years of experience with graphitic inks, that previously achieved industry-best conductivity of 500,000 Sm-¹ (several times more conductive than other non-metal inks) - the latest breakthrough seems to significantly raise the bar. 

Hot-carrier transistors are a class of devices that leverage the excess kinetic energy of carriers. Unlike regular transistors, which rely on steady-state carrier transport, hot-carrier transistors modulate carriers to high-energy states, resulting in enhanced device speed and functionality. These characteristics are essential for applications that demand rapid switching and high-frequency operations, such as advanced telecommunications and cutting-edge computing technologies. However, their performance has been limited by how hot carriers have traditionally been generated.

A team of researchers, led by Prof. Liu Chi, Prof. Sun Dongming, and Prof. CHeng Huiming from the Institute of Metal Research (IMR) of the Chinese Academy of Sciences, has proposed a novel hot carrier generation mechanism called stimulated emission of heated carriers (SEHC). The team has also developed an innovative hot-emitter transistor (HOET), achieving an ultralow sub-threshold swing of less than 1 mV/dec and a peak-to-valley current ratio exceeding 100. The study provides a prototype of a low power, multifunctional device for the post-Moore era.

Researchers have used a specially crafted electric potential to manipulate the electronic band structure of graphene, laying the groundwork for on-demand electronic band design. 

Scientists have long been trying to tune the electronic band structures of materials so that those materials exhibit desired physical properties. In the past few years, researchers have shown they can manipulate the band structures of graphene and other 2D materials using electric-field configurations that produce simple periodic potentials. Now, Changgan Zeng at the University of Science and Technology of China and his colleagues have shown that they can achieve greater control over the band structure using an electric potential with a shape that resembles a basket-weaving pattern known as kagome.