NIST team brings nanofluidics computing closer to reality

Computers based on fluids instead of silicon is not a new concept, and now researchers at the National Institute of Standards and Technology (NIST) have shown how computational logic operations could be performed in a liquid medium by simulating the trapping of ions (charged atoms) in graphene floating in saline solution. The scheme might also be used in applications such as water filtration, energy storage or sensor technology.

Researchers simulate simple logic for nanofluidic computing image

NIST's ion-based transistor and logic operations are simpler in concept than earlier proposals. The new simulations show that a special film immersed in liquid can act like a solid silicon-based semiconductor. For example, the material can act like a transistor, the switch that carries out digital logic operations in a computer. The film can be switched on and off by tuning voltage levels like those induced by salt concentrations in biological systems.

Graphenea launches new GFET products

Graphenea has launched sales of GFETs (graphene field effect transistors) aimed at lowering barriers to adoption of graphene, especially the sensors market. Researchers needing GFETs for their applications, whether in gas, biosensing, or other applications, can now purhcase high-quality GFET devices.

Graphenea launches GFETs imageGraphenea's new GFETs image

Graphenea has started by launching two standard GFET-for-sensing configurations called GFET-S10 and GFET-S20, each including 36 individual GFETs on a one square centimeter die, but differing in device layout. The GFET-S10 has devices distributed evenly over the die and the GFET-S20 has the devices concentrated in the center of the die with electrical pads located at the die edge. The GFET-S20 devices all have a 2-probe geometry for probing electrical properties during sensing, whereas the GFET-S10 houses 30 devices with the Hall bar geometry and 6 with 2-probe geometry. The Hall bars enable magnetic field sensing, apart from applications in graphene device research, bioelectronics, biosensing, chemical sensing, and photodetectors that the 2-probe geometry also allows.

Graphene can be tuned to behave as both an insulator and a superconductor

Researchers at MIT and Harvard University have found that graphene can be tuned to behave at two electrical extremes: as an insulator, in which electrons are completely blocked from flowing; and as a superconductor, in which electrical current can stream through without resistance.

MIT and Harvard team create graphene ''superlattice'' that can be superconductive and insulating image

Researchers in the past, including this team, have been able to synthesize graphene superconductors by placing the material in contact with other superconducting metals — an arrangement that allows graphene to inherit some superconducting behaviors. In this new work, the team found a way to make graphene superconduct on its own, demonstrating that superconductivity can be an intrinsic quality in the purely carbon-based material.

Graphene on hBN transistor displays remarkable cooling properties

Researchers from the Pierre Aigrain Laboratory in the ENS Physics department in Paris, France, have discovered a new cooling mechanism for electronic components made of graphene deposited on boron nitride. The efficiency of this mechanism reportedly allowed the team to reach electric intensities at the intrinsic limit of the laws of conduction.

ENS graphene transistor results imageCurrent-voltage (left) and temperature-voltage (right) characteristics of a graphene on boron nitride transistor. The transistor effect is visible by modulation of the current as a function of the gate voltage in the Zener-Klein tunnel transport regime.

Heat dissipation is vital in order to prevent deterioration or destruction of electronic components. The laws of physics dictate that increasing the density of components on a chipset implies increasing dissipation and thus heat. Nowadays, with the advances in 2D material devices, this question becomes particularly critical since components are required to be one atom thick. By producing a graphene-based transistor deposited on a boron nitride substrate, the team demonstrated a new cooling mechanism 10 times more efficient than basic heat diffusion. This new mechanism, which exploits the two-dimensional nature of the materials opens a "thermal bridge" between the graphene sheet and the substrate.

International team produces nano-transistors from carefully controlled GNRs

An international team of researchers from Empa, the Max Planck Institute for Polymer Research in Mainz and the University of California at Berkeley has succeeded in growing graphene ribbons exactly nine atoms wide with a regular armchair edge from precursor molecules. The specially prepared molecules are evaporated in an ultra-high vacuum for this purpose. After several process steps, they are put on a gold base to form the desired nanoribbons of about one nanometer in width and up to 50 nanometers in length.

Researchers create GNR-based transistors image

These structures have a relatively large and, most importantly, precisely defined energy gap. This enabled the researchers to go one step further and integrate the graphene ribbons into nanotransistors. Initially, however, the first attempts were not so successful: Measurements showed that the difference in the current flow between the "ON" state (i.e. with applied voltage) and the "OFF" state (without applied voltage) was far too small. The problem was the dielectric layer of silicon oxide, which connects the semiconducting layers to the electrical switch contact. In order to have the desired properties, it needed to be 50 nanometers thick, which in turn influenced the behavior of the electrons.

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