Ultra-fast Data Processing At Nanoscale

Advancement in nanoelectronics, which is the use of nanotechnology in electronic components, has been fueled by the ever-increasing need to shrink the size of electronic devices like nanocomputers in a bid to produce smaller, faster and smarter gadgets such as computers, memory storage devices, displays and medical diagnostic tools.

While most advanced electronic devices are powered by photonics – which involves the use of photons to transmit informationphotonic elements are usually large in size and this greatly limits their use in many advanced nanoelectronics systems. Plasmons, which are waves of electrons that move along the surface of a metal after it is struck by photons, holds great promise for disruptive technologies in nanoelectronics. They are comparable to photons in terms of speed (they also travel with the speed of light), and they are much smaller. This unique property of plasmons makes them ideal for integration with nanoelectronics. However, earlier attempts to harness plasmons as information carriers had little success.

Addressing this technological gap, a research team from the National University of Singapore (NUS) has recently invented a novel “converter” that can harness the speed and small size of plasmons for high frequency data processing and transmission in nanoelectronics.

This innovative transducer can directly convert electrical signals into plasmonic signals, and vice versa, in a single step. By bridging plasmonics and nanoscale electronics, we can potentially make chips run faster and reduce power losses. Our plasmonic-electronic transducer is about 10,000 times smaller than optical elements. We believe it can be readily integrated into existing technologies and can potentially be used in a wide range of applications in the future,” explained Associate Professor Christian Nijhuis from the Department of Chemistry at the NUS Faculty of Science, who is the leader of the research team behind this breakthrough.

This novel discovery was first reported in the journal Nature Photonics.

Source: http://news.nus.edu.sg/

Electric Power: How To Increase Solar Cells Efficiency

Rice University researchers have demonstrated an efficient new way to capture the energy from sunlight and convert it into clean, renewable energy by splitting water molecules.

Hot elsplitting water Riceectrons have the potential to drive very useful chemical reactions, but they decay very rapidly, and people have struggled to harness their energy,” said lead researcher Isabell Thomann, assistant professor of nanoengineering at Rice. “For example, most of the energy losses in today’s best photovoltaic solar panels are the result of hot electrons that cool within a few trillionths of a second and release their energy as wasted heat.” Capturing these high-energy electrons before they cool could allow solar-energy providers to significantly increase their solar-to-electric power-conversion efficiencies  and reduce  the cost of solar electricity.

In the light-activated nanoparticles studied by Thomann and colleagues at Rice’s Laboratory for Nanophotonics (LANP), light is captured and converted into plasmons, waves of electrons that flow like a fluid across the metal surface of the nanoparticles. Plasmons are high-energy states that are short-lived, but researchers at Rice and elsewhere have found ways to capture plasmonic energy and convert it into useful heat or light. Plasmonic nanoparticles also offer one of the most promising means of harnessing the power of hot electrons, and LANP researchers have made progress toward that goal in several recent studies.

Thomann and her team created a system that uses the energy from hot electrons to split molecules of water into oxygen and hydrogen. That’s important because oxygen and hydrogen are the feedstocks for fuel cells, electrochemical devices that produce electricity cleanly and efficiently.

Because of the inherent inefficiencies, we wanted to find a new approach to the problem,” Thomann said. “We took an unconventional approach: Rather than driving off the hot electrons, we designed a system to carry away the electron holes. In effect, our setup acts like a sieve or a membrane. The holes can pass through, but the hot electrons cannot, so they are left available on the surface of the plasmonic nanoparticles.”

The technology, is described online in the American Chemical Society journal Nano Letters.

-Soiurce: http://news.rice.edu/

 

How To Detect Infections At Extremely Low Cost

Detecting HIV/AIDS, tuberculosis, malaria and other deadly infectious diseases as early as possible helps to prevent their rapid spread and allows for more effective treatments. But current detection methods are cost-prohibitive in most areas of the world. Now a new nanotechnology method—employing common, everyday shrink wrap— may make highly sensitive, extremely low-cost diagnosis of infectious disease agents possible. The research team conducted by co-author Michelle Khine, a biomedical engineering professor at the University of California, Irvine (UC Irvine) found that the shrink wrap’s wrinkles significantly enhanced the intensity of the signals emitted by the biomarkers. The enhanced emission, Khine says, is due to the excitation of localized surface plasmons—coherent oscillations of the free electrons in the metal. When researchers shined a light on their wrinkled creation, the electromagnetic field was amplified within the nanoscale gaps between the shrink wrap’s folds, Khine said. This produced “hotspots”—areas characterized by sudden bursts of intense fluorescence signals from the biomarkers.

Using commodity shrink wrap and bulk manufacturing processes, we can make low-cost nanostructures to enable fluorescence enhancements greater than a thousand-fold, allowing for significantly lower limits of detection,” said Michelle Khine,. “If you have a solution with very few molecules that you are trying to detect—as in the case of infectious diseases — this platform will help amplify the signal so that a single molecule can be detected.The technique should work with measuring fluorescent markers in biological samples, but we have not yet tested bodily fluids,” said Khine, who cautions that the technique is far from ready for clinical use.

The findings have been described in a paper published in The Optical Society’s (OSA) journal Optical Materials Express.

Source: http://www.osa.org/

Integration Of Photonic And Electronic Components

Better integration of photonic and electronic components in nanoscale devices may now become possible, thanks to work by Khuong Phuong Ong and Hong-Son Chu from the A*STAR Institute of High Performance Computing and their co-workers in Singapore and the US. From computer simulations, they have identified that the compound BiFeO3 has the potential to be used to efficiently couple light to electrical charges through light-induced electron oscillations known as plasmons. The researchers propose that this coupling could be activated, controlled and switched off, on demand, by applying an electrical field to an active plasmonic device based on this material. If such a device were realized on a very small footprint it would give scientists a versatile tool for connecting components that manipulate light or electric currents.

poles
Thin poles standing in water barely affect waves rolling past them. Similarly, nanostructured devices typically do not interact with light waves

Many devices used in everyday life — whether they be televisions, mobile phones or barcode scanners — are based on the manipulation of electric currents and light. At the micro- and nano-scales, however, it is typically challenging to integrate electronic components with photonic components. At these small dimensions, the wavelengths of light become long relative to the size of the device. Consequently, the light waves are barely detectable by the device, just as passing waves simply roll past thin poles in a water body (see image).

Source: http://www.research.a-star.edu.sg/research/6656