IBM researchers built a graphene (GFET) based radio frequency receiver IC which they say is the world's most advanced IC ever made of graphene - in fact it offers 10,000 times better performance and any previously reported effort.

IBM's circuit consists of three graphene transistors, four inductors, two capacitors, and two resistors. All circuit components are fully integrated into a 0.6 mm² area and fabricated in a 200 mm silicon production line. The researchers say that those the circuits consume less than 20 mW power to operate, while also demonstrating the highest conversion gain of any graphene RF circuits at multiple GHz frequency.

Researchers from Korea's Ulsan National Institute of Science and Technology (UNITS) developed new graphene-based FETs (G-FETs), based on boron/nitrogen co-doped graphene nanoplatelets.

The researchers major breakthrough is the development of a new efficient method to produce those BCN-graphene platelets via a simple solvothermal reaction using potassium. Doping the GNPs opens up a bandgap.

Korean researchers developed a liquid-ion gated FET-type graphene-based aptasensor with highly sensitive and selective responses to various mercury ion concentrations. This sensor was shown to be a good detector of mercury in mussels.

Aptasensors are bio-sensors that use aptamers (artificial oligonucleotides: DNA or RNA) as a recognition element. The sensors developed in korea used a single-layer graphene sheet that was functionalized using an aptamer. This sensor is not just very sensitive and fast, but it's also flexible and highly stable mechanically.

A few days ago we reported on Bluestone Global Tech's new graphene based Field Effect Transistors. We have discussed it with BGT and have some more details on this exciting development. So first of all, we reported that the Gray-FETs are currently offered for research only, but BGT says that they are using a fab that can produce these in volume "to meet most demands". So this is suitable for commercial applications.

In fact BGT is already in talks with several academic and industrial customers. Having a standard GFET product can save a lot of time and will enable those customers to develop their own products based on these transistors faster then if they need to first develop the GFET themselves.

Bluestone Global Tech announced a new groundbreaking product today, the world's first graphene based Field Effect Transistor. BGT's Grat-FET is a wafer with 9 different GFET chips (or FET arrays), each with 64 FETs. Grat-FET is aimed towards research and development work and not for commercial production.

BGT's GFETs are fabricated (using CVD) on a silicon wafer covered with a SiO₂ layer. The high mobility (2000 cm²/Vs or more) graphene is used as the transistor channel. Each transistor consists of three terminals: source and drain metal electrodes and a global back gate.

Researchers from the University of California, Riverside developed a graphene based transistor based on negative resistance rather than trying to open up a band gap. Negative resistance is the counterintuitive phenomenon in which a current entering a material causes the voltage across it to drop. It was shown before that graphene demonstrates negative resistance in certain circumstances.

The idea is to take a regular graphene field-effect transistor (FET) and find the circumstances in which it demonstrates negative resistance. This dip in voltage is used as a kind of switch - to perform logic. The researchers showed how several graphene FETs combined can be manipulated to produce conventional logic gates. The researchers designed such circuits that can match patterns (but they have yet to actually produce them).

Researchers from the University of Texas at Austin have developed flexible graphene field-effect transistors (G-FET) that features record current densities and the highest power and conversion gain ever. The team says that the transistors show near symmetric electron and hole transport and are the most mechanically robust flexible graphene devices fabricated to date. They are also resistant to water.

The G-FETs were made directly atop patterned dielectrics on plastic sheets using conventional microelectronic lithography. In those devices, multi-finger metal gate electrodes are embedded in the plastic sheet. The graphene was grown using CVD.

Researchers from the HRL labs in California have developed the world’s first graphene-based square-law millimeter detectors. These new detectors sport the highest linear dynamic range (over 60 dB) ever measured in a semiconductor detector. They say that this could lead to better high-bandwidth communications, imaging and radar systems.

The researchers say that their new graphene-based FET detectors out perform the best CMOS or SiGe bipolar detectors by more than 30 dB (linear dynamic range).

A research team from Chalmers University of Technology in Sweden developed a new subharmonic graphene FET mixer at microwave frequencies. This could pave the way for new opportunities in future electronics as it enables compact circuit technology, potential to reach high frequencies and integration with silicon technology.

A mixer combines two (or more) electronic signals into one or two composite output signals. The ability in graphene to switch between hole or electon carrier transport via the field effect requires a unique niche for graphene for rf ic applications. The researchers say this symmetrical electrical characteristic has enabled them to build a G-FET subharmonic resistive mixer using only one transistor.

IBM researchers has fabricated a 2-GHz graphene frequency doubler RF circuit in a CMOS-compatible manufacturing process, on 8" wafers. To fabricate this the researchers inverted the usual manufacturing process and define gate structures first on silicon wafers and then transfer graphene layers fabricated using chemical vapor deposition to the silicon. After defining the areas of graphene IBM was able to attach source and drain contacts to the graphene to complete FET structures.

Inverted-T gate structure

The device itself, the frequency doubler, integrates multiple field effect transistors and radio frequency passives and demonstrated a conversion gain of approximately -25db (at 2 Ghz).