Manipulating electron spin in graphene may enable ambient-temperature FETs

Jul 09, 2017

Researchers at Chalmers University, affiliated with the Graphene Flagship, have devised a graphene-based spin field-effect transistor with the ability to function at room temperature. The team used the spin of electrons in graphene and similar layered material heterostructures to fabricate working devices in a step towards combining memory devices and the logic of spintronics.

Graphene spintronics FETs image

The researchers demonstrated that the spin characteristics of graphene can be electrically regulated in a controlled way, even at an ambient temperature. In addition to possibly unlocking various probabilities in spin logic operations, this study also enables integration with magnetic memory elements in a device unit. If further advancements can assist in the production of a spin current without the need for charge flow, the amount of power needed will be considerably reduced, resulting in highly versatile devices.

Graphene-based transistor to potentially make ultra-fast computers

Jun 14, 2017

Researchers at the University of Central Florida, the University of Texas at Dallas and other collaborators have designed a graphene-based transistor which could be used to create an all-carbon spin logic design with the potential to someday lead to computers that are a thousand times faster and use a hundredth of the power.

UCF's GNR's for  graphene transistor image

The team found that by applying a magnetic field to a graphene ribbon, it is possible to change the resistance of current flowing through it. For this device, the magnetic field is controlled by increasing or decreasing the current through adjacent carbon nanotubes. Increasing or decreasing the strength of the magnetic field would also increase or decrease the flow of current through this new kind of transistor, much like a valve controlling the flow of water through a pipe.

High performance graphene transistors developed by Graphene Flagship researchers

Jun 07, 2017

An international team of scientists collaborating in the Graphene Flagship project has developed a graphene-based transistor that reportedly outperforms previous state-of-the-art ones. The team utilized a thin top gate insulator material to optimize operational properties like maximum oscillation frequency, cutoff frequency, forward transmission coefficient, and open-circuit voltage gain, realizing devices that show prospect of using graphene in a wide range of electronic applications.

Graphene Flagship team develops high performance graphene transistors image

Graphene lack of a bandgap hinders its use in electronics since it causes an inability to switch the transistors off, effectively rendering the “0” state in digital logic inaccessible. However, many analog applications do not require a bandgap; The team explains that the only undesired side-effect of using GFETs in analog circuits is a poor saturation of the drain current, which prevents high-gain operation. The researchers have now succeeded in improving saturation by optimizing the dielectric material (AlOx) that is used to electrically insulate the top gate of the GFET. An improved quality of gate dielectric resulted in strong control over carriers in the graphene channel, yielding overall performance benefits.

Graphene-based transistors show promise for optical technologies

Apr 18, 2017

Researchers at Purdue University, the University of Michigan and Pennsylvania State University have combined graphene with a (comparatively much larger) silicon carbide substrate, creating graphene field-effect transistors which can be activated by light. This may lead to the development of highly sensitive graphene-based optical devices, an advance that could bring applications from imaging and displays to sensors and high-speed communications.

GFETs show promise for optical technologies image

A typical problem of graphene-based photodetectors is that they have only a small area that is sensitive to light, limiting their performance. “In typical graphene-based photodetectors demonstrated so far, the photoresponse only comes from specific locations near graphene over an area much smaller than the device size,” the team said. “However, for many optoelectronic device applications, it is desirable to obtain photoresponse and positional sensitivity over a much larger area”. The researchers tackled exactly this in their new work.

Graphene Flagship team creates transistors printed with graphene and other layered materials

Apr 09, 2017

Graphene Flagship researchers from AMBER at Trinity College Dublin, in collaboration with scientists from TU Delft, Netherlands, have fabricated printed transistors consisting entirely of layered materials. The team's findings are said to have the potential to cheaply print a range of electronic devices from solar cells to LEDs and more.

The team used standard printing techniques to combine graphene flakes as the electrodes with other layered materials, tungsten diselenide and boron nitride as the channel and separator to form an all-printed, all-layered materials, working transistor.

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