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Improved graphene-based transistors to detect disease-causing genes

Feb 26, 2017

Researchers in India and Japan have developed an improved method for using graphene-based transistors to detect disease-causing genes.

GFETs to detect harmful genes image

The team improved sensors that can detect genes through DNA hybridization, which occurs when a 'probe DNA' combines with its complementary 'target DNA.' Electrical conduction changes in the transistor when hybridization occurs. The improvement was done by attaching the probe DNA to the transistor through a drying process. This eliminated the need for a costly and time-consuming addition of 'linker' nucleotide sequences, which have been commonly used to attach probes to transistors.

Graphenea, Nokia and IEMN-CNRS collaborate to create high-frequency graphene transistors on flexible substrates

Feb 21, 2017

Scientists from IEMN-CNRS, Graphenea, and Nokia have demonstrated flexible graphene transistors with a record high cut-off frequency of 39 GHz. The graphene devices, made on flexible polymer substrates, are stable against bending and fatigue of repeated flexing.

Graphenea and Nokia create impressive GFET image

The graphene field effect transistor (GFET) is made from high quality CVD grown graphene with a carrier mobility of ~2500 cm2 V-1 s-1 on a flexible Kapton substrate with a thin alumina dielectric spacer in the channel region. The use of such sophisticated and optimized materials leads to the record high frequency performance as well as stability against bending. The GFET reportedly continues to operate even after 1,000 bending cycles and can be flexed to a radius of 12 mm with a cutoff frequency shift of up to 10%.

Industrial-academic collaboration develops stable and consistent graphene electronic devices

Feb 02, 2017

Researchers from Graphenea, Thales, CNRS, the University of Cambridge and GERAC have announced the development of a stable platform for manufacturing electronic devices made of graphene. Graphene field effect transistors (GFETs) made using this platform are shown to be stable against atmospheric influences and uniform in their properties across a batch of more than 500 devices.

Graphenea and cambridge develop a platform for graphene electronics production image

The researchers reported on a statistical analysis and consistency of electrical performance of GFETs on a large scale. The devices were protected and passivated with two protective layers that ensured that the conductance minimum characteristic of electrical transport in graphene is visible most of the time and that it fluctuates very little from device to device. The intrinsic charge doping was below 5x1011 cm-2. In addition, this approach removed the hysteresis effect that usually degrades graphene device performance in air. Importantly, the devices were also stable in time, with unchanged performance over the course of one month.

Fujitsu developed a novel graphene gate transistor based gas sensor

Nov 16, 2016

Researchers from Fujitsu present a new novel graphene-enhanced gas sensor device. The graphene has been employed as gate electrode for an n-channel silicon transistor. The researchers report that the sensor exhibits sensitivities that are more than one order of magnitde better than conventional resistivity-based graphene gas sensors - easily detecting 7 ppb of No2.

Graphene gate transistor for gas sensing image (Fujitsu)

When the graphene gate is exposed and gas molecules adsorb on the graphene surface, the work function of graphene changes depending on the gas species and concentrations, thus changing the threshold of the silicon transistor. The work function of the graphene-gate can be controlled by intentionally depositing proper doping materials on graphene, changing the threshold by up to 620 mV without degrading the sub threshold properties.

Graphene and MoS2 used by Berkeley Lab to make a transistor

Jul 12, 2016

Researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a way to assemble transistors based on graphene and molybdenum disulfide.

Graphene-MOS2 transistor image

The method etches narrow channels in conducting graphene laid down on a silicon-dioxide substrate. These channels are then filled with the 2D MoS2. The method allows graphene to inject electrons into the conduction band of the MoS2 channel with improved performance compared with simply using metal contacts to inject electrons, according to the researchers.