Researchers demonstrate Doppler effect and sonic boom in graphene devices

A team of researchers from universities in Loughborough, Nottingham, Manchester, Lancaster and Kansas (US) has revealed that sonic boom and Doppler-shifted sound waves can be created in a graphene transistor.

When a police car speeds past you with its siren blaring, you hear a distinct change in the frequency of the siren’s noise. This is the Doppler effect. When a jet aircraft’s speed exceeds the speed of sound (about 760 mph), the pressure it exerts upon the air produces a shock wave which can be heard as a loud supersonic boom or thunderclap. This is the Mach effect. The scientists discovered that a quantum mechanical version of these phenomena occurs in an electronic transistor made from high-purity graphene.

Read the full story Posted: Nov 09,2021

Combining graphene transistors with MOFs yields selective and sensitive sensors

Karlsruhe Institute Of Technology (KIT) and Technical University of Darmstadt researchers have developed graphene-enhanced sensors for molecules in the gas phase. The functional principle of this new type of sensors is based on sensitive graphene transistors and tailor-made organometallic coatings. This combination enables selective detection of molecules.

Process flow of graphene MOFs sensors imageFabrication of SURMOF/GFET process flow. Image from article

As a prototype, the authors of the new study demonstrated a specific ethanol sensor that, unlike currently available commercial sensors, does not react to other alcohols or moisture.

Read the full story Posted: Sep 13,2021

Researchers succeed in creating single-crystal, large-area, fold-free monolayer graphene

A team of researchers, led by Director Rod Ruoff at the Center for Multidimensional Carbon Materials (CMCM) within the Institute for Basic Science (IBS) and including graduate students at the Ulsan National Institute of Science and Technology (UNIST), has achieved growth and characterization of large area, single-crystal graphene totally free from wrinkles, folds, or adlayers. It was said to be 'the most perfect graphene that has been grown and characterized, to date'.

Director Ruoff notes: This pioneering breakthrough was due to many contributing factors, including human ingenuity and the ability of the CMCM researchers to reproducibly make large-area single-crystal Cu-Ni(111) foils, on which the graphene was grown by chemical vapor deposition (CVD) using a mixture of ethylene with hydrogen in a stream of argon gas. Student Meihui Wang, Dr. Ming Huang, and Dr. Da Luo along with Ruoff undertook a series of experiments of growing single-crystal and single-layer graphene on such ‘home-made’ Cu-Ni(111) foils under different temperatures.

Read the full story Posted: Aug 27,2021

Graphenea Foundry: a platform for the manufacture of graphene-based devices

This is a sponsored post by Graphenea

Graphenea’s Semiconductor catalogue spans from 1x1 cm2 single layer graphene films on a variety of substrates, to fully customized graphene-based device architectures implemented on wafers up to 150mm. The unique vertical integration that Graphenea offers, that covers the graphene growth, its transfer, its device fabrication and post-processing, allows Graphenea to have full control of the manufacturing process, continuously monitoring this through quality control processes and checkpoints.

GFET wafers (Graphenea)

Graphenea Foundry offers three products and services, which cover all the graphene needs one may have.

Read the full story Posted: Aug 17,2021

Graphene-diamond junctions could assist in the realization of neuromorphic optical computers simulating human visual memory systems

Researchers from Nagoya University in Japan have designed highly efficient computing devices using graphene-diamond junctions that mimic some of the human brain's functions.

Schematics of optoelectronic synaptic functions of vertically aligned graphene/diamond junctions image

A phenomenon crucial for memory and learning is "synaptic plasticity," the ability of synapses (neuronal links) to adapt in response to increased or decreased activity. Scientists have tried to recreate a similar effect using transistors and "memristors" (electronic memory devices whose resistance can be stored). Recently developed light-controlled memristors, or "photomemristors," can both detect light and provide non-volatile memory, similar to human visual perception and memory. These excellent properties have opened the door to new materials that can act as artificial optoelectronic synapses.

Read the full story Posted: Aug 04,2021

Cardea Bio partners with Scentian Bio to create a bio-electronic tongue/nose platform

Cardea Bio, a biotech company integrating molecular biology with semiconductor electronics, has signed a commercial partnership with Scentian Bio. Scentian is an expert in synthetic insect odorant receptors (iORs), one of nature’s ways of detecting and interpreting smells.

The partnership will enable Scentian to use a customized Cardean chipset, built with graphene-based biology-gated transistors, which will allow Scentian to manufacture a bio-electronic tongue/nose tech platform.

Read the full story Posted: May 18,2021

Researchers show that the terahertz nonlinearity of graphene can be efficiently controlled using minimal electrical gating

A team of researchers from Bielefeld and Berlin, together with researchers from other research institutes in Germany and Spain, recently demonstrated that graphene's nonlinearity can be efficiently controlled by applying comparatively modest electrical voltages to the material.

The gated graphene sample device in which the graphene film acts as a channel between source and drain electrodes  imageThe gated graphene sample device in which the graphene film acts as a channel between source and drain electrodes subjected to a constant potential difference of 0.2 mV. Image from Science Advances

It was recently discovered that the high electronic conductivity and "massless" behavior of graphene's electrons allows it to alter the frequency components of electric currents that pass through it. This property is highly dependent on how strong this current is. In modern electronics, such a nonlinearity comprises one of the most basic functionalities for switching and processing of electrical signals. What makes graphene unique is that its nonlinearity is by far the strongest of all electronic materials. Moreover, it works very well for exceptionally high electronic frequencies, extending into the technologically important terahertz (THz) range where most conventional electronic materials fail.

Read the full story Posted: Apr 15,2021

Cardea Bio and the Georgia Tech Research Institute enter DARPA agreement to develop airborne SARS-CoV-2 sensors

The Defense Advanced Research Projects Agency (DARPA) recently awarded the Georgia Tech Research Institute (GTRI) an agreement, as part of their SenSARS program, to develop a sensing platform to detect airborne SARS-CoV-2 particles. Cardea Bio is a sub-contractor to this agreement.

This agreement will enable the two institutions to develop a real-time pathogen identification technology that can be applied to many different defense and civilian environmental monitoring applications.

Read the full story Posted: Mar 05,2021

Graphene ‘nano-origami’ could enable tiny microchips

Scientists at the University of Sussex have developed a technique for making tiny microchips from graphene and other 2D materials, using a form of ‘nano-origami’.

By creating distortions in the structure of the graphene, the researchers were able to make the nanomaterial behave like a transistor. We’re mechanically creating kinks in a layer of graphene, says Professor Alan Dalton of the School of Mathematical and Physics Sciences at the University of Sussex. It’s a bit like nano-origami. Using these nanomaterials will make our computer chips smaller and faster. It is absolutely critical that this happens as computer manufacturers are now at the limit of what they can do with traditional semiconducting technology. Ultimately, this will make our computers and phones thousands of times faster in the future.

Read the full story Posted: Feb 16,2021

Researchers design an accurate, high-speed, portable bifunctional electrical detector for COVID-19

A research team at South China University of Technology, Peking University and other China-based universities have developed an accurate, rapid, and portable electrical detector based on the use of graphene field-effect transistors (G-FETs) for detection of RNA from COVID-19 patients.

Schematic diagram of the operation procedure of our G-FET-based biosensing system for COVID-19 image

The detection system consists of two main parts: a plug-and-play packaged biosensor chip and an electrical measurement machine. The unique feature of this method is that the extent of hybridization between the ss-DNA probe and viral RNA can be directly converted to the current change of graphene channels without repetition of the PCR process. Furthermore, this method was validated using clinical samples collected from many patients with COVID-19 infection and healthy individuals as well, and the testing results were in full agreement with those of PCR-based optical methods.

Read the full story Posted: Jan 26,2021