Graphene is the next-generation miracle semiconductor material, many believe, but it is hard to work with and harder to mass produce. The Swiss Federal Institute of Technology (ETH) now believes it has the an answer–combine graphene with organic proteins to create a conductive paper from which future electronic devices can be fabricated: R. Colin Johnson
The final hybrid nanocomposite paper made of protein fibrils and graphene after vacuum filtration drying. The schematic route used by the researchers to combine graphene and protein fibrils into the new hybrid nanocomposite paper. (Reproduced from Li et al. Nature Nanotechnology 2012) [via]
Graphene + Proteins Enabling Cheap Semiconductors - [Link]
Sebastian Anthony writes:
Numerous research groups around the world are reporting that they have created silicene, a one-atom-thick hexagonal mesh of silicon atoms — the silicon equivalent of graphene.
Since its discovery a few years ago, you will have heard a lot about graphene, especially with regard to its truly wondrous electrical properties. Graphene is the most conductive material in the known universe, and IBM has shown that graphene transistors could be become the basis of transistors (and computers) that operate in the hundreds-of-gigahertz or terahertz (THz) range. There’s only one problem: Graphene isn’t really a semiconductor in the silicon/computer chip sense of the word. Unlike silicon (or germanium), graphene doesn’t have a bandgap, which makes it very hard to actually build a switching device — such as a transistor — out of it. Researchers have had some luck in introducing a bandgap, but graphene is still a long way away from being used in current silicon processes.
Single-layer silicon that could beat graphene to market - [Link]
Scientists and engineers at the University of Wisconsin-Milwaukee have accidentally discovered an entirely new carbon-based material that is synthesized from graphene. The new material that the researchers are calling graphene monoxide unifies all three characteristics of electrical conductivity – conduction, insulation and semi-conduction – which are needed for use in electronics.
Graphene has the potential to revolutionize electronics because it conducts electricity much better than the gold and copper wires used in current devices. Applications for graphene however are limited because it’s too expensive to mass produce. Another problem is that, until now, graphene-related materials existed only as conductors or insulators.
The researchers created the new material by heating grapheme oxide (GO) in a vacuum to reduce oxygen. Instead of being destroyed, however, the carbon and oxygen atoms in the layers of GO became aligned, transforming themselves into the ordered, semiconducting graphene monoxide (GMO) – a material that does not exist in nature. It was not the result they expected. The new GMO exhibits characteristics that will make it easier to scale up than grapheme and it is semiconducting. [via]
Accidental Discovery Advances Graphene-based Electronics - [Link]
Supercapacitors can store substantially more charge than regular capacitors and they charge and discharge faster than batteries. Unfortunately they only have a fraction of the energy density of batteries. Improving the energy density of supercapacitors would represent a significant advance in energy storage technology, but this requires electrodes that not only maintain high conductivity but also provide higher and more accessible surface area than conventional activated carbon electrodes.
Researchers at UCLA have now produced laser scribed graphene electrodes that have these desired properties. The electrodes consist of an expanded network of graphene and have excellent mechanical and electrical properties, as well as exceptionally high surface area. The open network structure reduces the diffusion path of electrolyte ions, which is crucial for charging the device and also allows supercapacitors to deliver very high power in a short period of time. [via]
LightScribe DVD drive makes novel supercapacitor electrodes - [Link]
Researchers at Notre Dame have developed a solar cell that is remarkably easy to assemble because the middle layer can be painted onto a clear electrode. First, they mix t-butanol, water, cadmium sulfide and titanium dioxide for 30 minutes. Next, they mask off a clear electrode with office tape. Once the tape is in place, they spread the mixture onto the electrode and then anneal it with a heat gun. Finally, they sandwich an electrolyte solution between the new electrode and a graphene composite electrode. And then, it’s time for testing under a beam of artificial light.
Painting Solar Cells with Nanoparticle Paste - [Link]
Smaller and more energy-efficient electronic chips could be made using molybdenite. In an article appearing online January 30 in the journal Nature Nanotechnology, EPFL’s Laboratory of Nanoscale Electronics and Structures (LANES) publishes a study showing that this material has distinct advantages over traditional silicon or graphene for use in electronics applications.
A discovery made at EPFL could play an important role in electronics, allowing us to make transistors that are smaller and more energy efficient. Research carried out in the Laboratory of Nanoscale Electronics and Structures (LANES) has revealed that molybdenite, or MoS2, is a very effective semiconductor. This mineral, which is abundant in nature, is often used as an element in steel alloys or as an additive in lubricants. But it had not yet been extensively studied for use in electronics.
New Transistors: An Alternative to Silicon and Better Than Graphene - [Link]
This is so cool, and it has enormous potential — think nanotransponders for the Internet of Things (or sub-dermal radios). From nanotechweb: [via]
The first graphene device capable of significant voltage amplification (more than 10 dB) has been fabricated by researchers in Italy. The result confirms that the “wonder material” could compete head-on with silicon as the material of choice in electronics and is not simply limited to niche, low-voltage gain, high-frequency applications as currently thought.
The voltage amplifier (a device capable of amplifying small alternating voltage signals) is the main building block in analogue electronics. Thanks to its unique electrical and mechanical properties, graphene (a sheet of carbon atoms arranged in a honeycomb-like lattice just one atom thick) should be ideal for use in a host of technological devices – such as high-speed transistors – and in photonics. However, many scientists believe that it cannot compete with silicon in applications requiring voltage amplification, like analogue amplifiers and digital logic gates.
Even though it is their first graphene amplifier, it already shows “remarkable performance”, according to Sordan and colleagues – with a flat frequency response well exceeding the audio range (>20 kHz) and a very low total harmonic distortion (<1%).
Using Graphene to Build Nanoamplifiers - [Link]
This is interesting. Researchers are trying to improve Flash memory density and retention time by using graphene structures. From IEEE Spectrum: [via]
Nanotechnology has a somewhat infamous relationship with flash memory. It has usually taken on the role as its adversary, such as in the case of Nantero or IBM’s Millipede project, and walked away with less than encouraging results.
So I was interested to see that researchers were using graphene as a platform for flash memory that appears to outperform other flash memory structures. If you can’t beat ‘em, join ‘em.
Researchers from UCLA, IBM’s T.J. Watson Research Center, Samsung Electronics, Aerospace Corporation, and the University of Queensland, team led by Kang Wang have recently published in ACS Nano an article entitled “Graphene Flash Memory” that demonstrates that graphene may have what it takes to outperform current flash memory technology.
As I have suggested in my post from last week, researchers are not breaking their backs trying to overcome graphene’s lack of band gap as much now as they are instead looking for ways to exploit its intrinsic strengths.
In this case, the researchers were trying to take advantage of graphene’s high density of states, high work function, and atomic thinness.
Graphene-based Flash Memory - [Link]
A combination of two ordinary materials – graphite and water – could produce energy storage systems that perform on par with lithium ion batteries, but recharge in a matter of seconds and have an almost indefinite lifespan.
Dr Dan Li, of the Monash University Department of Materials Engineering, and his research team have been working with a material called graphene, which could form the basis of the next generation of ultrafast energy storage systems.
“Once we can properly manipulate this material, your iPhone, for example, could charge in a few seconds, or possibly faster.” said Dr Li. [via]
Graphite + water = the future of energy storage - [Link]
Earlier this year we ran a story on molybdenite, a mineral that held an advantage over graphene for use in electronic devices due to the existence of “band gaps” in the material that are needed for devices such as transistors, computer chips and solar cells. Now MIT researchers have overcome that deficiency by finding a way to produce graphene in significant quantities in a two- or three-layer form with the layers arranged just right to give the material the much-desired band gap.
MIT researchers give graphene band gap and open the door for post-silicon electronic devices - [Link]