Chinese researchers design a silicon-graphene-germanium transistor for future THz operation

Researchers from the Chinese Academy of Sciences have fabricated a graphene-based transistor with a Schottky emitter - a silicon-graphene-germanium transistor. Using a semiconductor membrane and graphene transfer, the team stacked three materials including an n-type top single-crystal Si membrane, a middle single-layer graphene (Gr) and an n-type bottom Ge substrate.

A vertical silicon-graphene-germanium transistor inageDevice design and fabrication. Image credit: Nature Communications

The team explained that compared with previous tunnel emitters, the on-current of the Si-Gr Schottky emitter shows the maximum on-current and the smallest capacitance, leading to a delay time more than 1,000 times shorter. Thus, the alpha cut-off frequency of the transistor is expected to increase from about 1 MHz by using the previous tunnel emitters to above 1 GHz by using the current Schottky emitter. THz operation is expected using a compact model of an ideal device.

Groningen team creates graphene-based 2D spin transistor

Physicists from the University of Groningen constructed a two-dimensional spin transistor, in which spin currents were generated by an electric current through graphene. A monolayer of a transition metal dichalcogenide (TMD) was placed on top of the graphene to induce charge-to-spin conversion in the graphene.

Scientists create fully electronic 2-dimensional spin transistors image

Spintronics is an attractive alternative way of creating low-power electronic devices. It is not based on a charge current but rather on a current of electron spins. Spin is a quantum mechanical property of an electron, a magnetic moment that could be used to transfer or store information.

Graphene interconnects to advance high-speed super-computers

In November 2018, researchers from the University of California, Santa Barbara presented a paper on CMOS-compatible graphene interconnects. Following this work, a team of University of California Santa Barbara (UCSB) engineering researchers recently came out with a method to utilize nanometer-scale doped multilayer graphene (DMG) interconnects well suited to the mass-production of integrated circuits.

For more than 20 years interconnects have been manufactured using copper as the base material, yet, the limitations of this metal when shrinking it to the nanoscale resistivity increase, which poses a “fundamental threat to the $500 billion semiconductor industry,” say researchers at UCSB. Graphene holds the potential to resolve this issue as a global desire for smarter, faster, lighter and affordable technology and devices continues to expand.

Researchers produce graphene by mixing oxidized graphite with bacteria

Researchers at the U.S-based University of Rochester, along with colleagues at Delft University of Technology in the Netherlands, have designed a way to produce graphene materials using a novel technique: mixing oxidized graphite with bacteria. Their method is reportedly a more cost-efficient, time-saving, and environmentally friendly way of producing graphene materials versus those produced chemically, and could lead to the creation of innovative computer technologies and medical equipment.

Bacterially-made graphene is faster, cheaper and better imageFrom left to right:graphite (Gr), graphene oxide (GO), microbially‐reduced graphene oxide (mrGO), and chemically‐reduced graphene oxide (crGO)

"For real applications you need large amounts," says Anne S. Meyer, an associate professor of biology at the University of Rochester. "Producing these bulk amounts is challenging and typically results in graphene that is thicker and less pure. This is where our work came in". In order to produce larger quantities of graphene materials, Meyer and her colleagues started with a vial of graphite. They exfoliated the graphite-shedding the layers of material-to produce graphene oxide (GO), which they then mixed with the bacteria Shewanella. They let the beaker of bacteria and precursor materials sit overnight, during which time the bacteria reduced the GO to a graphene material.

Graphene biosensors detect cancer causing bacteria

Researchers at Osaka University have invented a graphene-based biosensor to detect bacteria such as those that attack the stomach lining and that have been linked to stomach cancer. When the bacteria interact with the biosensor, chemical reactions are triggered which are detected by the graphene.

Graphene-based sensors detect cancer-causing bacteria image

To enable detection of the chemical reaction products, the researchers used microfluidics to contain the bacteria in extremely tiny droplets close to the sensor surface.

Versarien - Think you know graphene? Think again! Versarien - Think you know graphene? Think again!