A team of Columbia Engineering researchers, led by Mechanical Engineering Professor James Hone and Electrical Engineering Professor Kenneth Shepard, exploring the properties of graphene have demonstrated a new electro-mechanical resonant component.
The resonator’s structure consists of a 2-4 micrometer long strip of graphene suspended over a metal gate electrode. The strip of graphene has a natural resonance governed by its physical dimension and is used in the demonstration as the frequency determining element in an RF feedback oscillator circuit. Applying a voltage to the gate electrode stresses and deflects the graphene strip changing its resonant frequency. The team applied baseband audio and tones to the gate electrode to produce a 100 MHz FM signal.[via]
Tiny FM Transmitter uses Voltage Controlled Graphene Resonator - [Link]
Graphene is by definition flat and planar, but researchers at Michigan Tech have discovered a manner of fabricating 3-D graphene–a honeycomb structure that can replace the expensive precious metals in solar cells and potentially other energy applications such as batteries and even superconductors. [via]
3D Graphene for Cheaper Solar Cells - [Link]
A team of researchers at Brown University (USA) has concluded that graphene, a material touted to replace silicon in future semiconductor devices, disrupts functions of living cells. If the results of the study are confirmed by others, graphene could end up in the same hazardous material category as carbon nanotubes.
Graphene has many unique properties, but from a toxicology perspective the most important is that it is often made as a dry powder with the potential for inhalation exposure. Graphene fragments that make up the powder have sharp, pointy edges that can penetrate cell walls and allow the rest of the fragment to be drawn into the cell.
The researchers started with toxicity studies of graphene, which showed that it did in fact disrupt cell functions. To discover why, atomically detailed computer simulations of the graphene material interacting with a living cell were created. The simulations indicated the same results as the toxicity experiments. After the simulations follow-up studies were performed on human lung, skin, and immune cells in Petri dishes, and they confirmed that graphene fragments as large as 10 microns can pierce and be swallowed up by living cells. [via]
Graphene a Possible Health Hazard? - [Link]
According to researchers at the Swedish Royal Institute of Technology (KTH) in Stockholm, graphene can increase the sensitivity of micro-electromechanical system (MEMS) sensors by up to 100 times due to exteme thinness of graphene films compared to other piezoresistive materials.
Piezoresistive pressure sensors typically integrate silicon piezoresistors into sensor membranes so that strain can be read in terms of resistance. The MEMS version suspends the membrane over a cavity by etching out the underying silicon dioxide. In the KTH version, an extremely thin layer of graphene is suspended over a cavity etched into a silicon dioxide layer on a silicon substrate. The extreme thinness of the graphene membrane – less than a nanometer with a monolayer membrane – increases the sensitivity of the electromechanical effect. [via]
Graphene Beats Silicon in Strain Gauges - [Link]
These recent breakthroughs in electrical component technology are likely to have a significant impact on the electronics industry – and on people’s everyday lives.
Your’e probably aware of the superstar conductor of the future, Graphene: “A wonder material that is the world’s thinnest, strongest and most conductive material with the potential to revolutionise diverse applications; from smartphones and ultrafast broadband to drug delivery and computer chips”.
New electronic components will change lives in 2014 - [Link]
The Massachusetts Institute of Technology (MIT) has discovered that pure crystalline carbon–graphene–sandwiched between two ferroelectric layers results in devices with built-in memory that operate in the terahertz range, potentially opening the door to next-generation applications: [via]
Terahertz Graphene Ferroelectrics Debut at MIT – [Link]
Research on graphene-based sensors at the Nanyang Technological University (NTU) in Singapore has yielded a new type of image sensor able to detect light over a broad spectrum, from the visible to mid-infrared, with very high sensitivity. In addition to being 1,000 times more sensitive to light than current low-cost imaging sensors used in compact cameras, it also uses 10 times less energy because it operates at a lower voltage. [via]
Graphene Photosensor is 1000x More Sensitive - [Link]
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]