In a development that could make the advanced form of secure communications known as quantum cryptography more practical, University of Michigan researchers have demonstrated a simpler, more efficient single-photon emitter that can be made using traditional semiconductor processing techniques.
To increase the neutron detection efficiency of bulk-micromegas (MICRO-MEsh GAseous Structure) neutron detectors, researchers from China and the University of Tennessee-Knoxville have proposed three new types of thin-film converters: micro-channel, parallel micro-pillar, and oblique micro-pillar 2D array. When validated using Monte Carlo simulations, the latter design showed a threefold increase in neutron detection efficiencies.
Certain semiconductors, when imparted with energy, in turn emit light; they directly produce photons, instead of producing heat. This phenomenon is commonplace and used in light-emitting diodes, or LEDs. Research from the University of Pennsylvania has enabled "bulk" silicon to emit broad-spectrum, visible light for the first time, opening the possibility of using the element in devices that have both electronic and photonic components.
Researchers sponsored by Semiconductor Research Corporation (SRC) have developed a modeling process designed to simulate atomic-level etching with chemicals that are effective alternatives to widely used perfluorocarbon (PFC) gases. The novel approach will identify and evaluate green plasma chemistries for processing emerging memory/logic devices and through-silicon-via (TSV)-enabled technologies for the semiconductor industry.
Semiconducting polymers are an unruly bunch, but University of Michigan engineers have developed a new method for getting them in line that could pave the way for cheaper, greener, "paint-on" plastic electronics.
MEH-PPV is a low-cost polymer that can be integrated with silicon chips, and researchers have sought to use it to convert electricity into laser light for use in photonic devices. However, attempts to do this have failed because the amount of electricity needed to generate laser light in MEH-PPV was so high that it caused the material to degrade. Researchers have recently come up with a low-cost way to enhance MEH-PPV’s ability to confine light, protecting the material.
Bringing the concept of an “artificial leaf” closer to reality, a team of researchers at Massachusetts Institute of Technology has published a detailed analysis of all the factors that could limit the efficiency of such a system. The new analysis lays out a roadmap for a research program to improve the efficiency of these systems, and could quickly lead to the production of a practical, inexpensive and commercially viable prototype.
Recent research offers a new spin on using nanoscale semiconductor structures to build faster computers and electronics. Literally. Researchers have revealed a new method that better preserves the units necessary to power lightning-fast electronics, known as qubits. Hole spins, rather than electron spins, can keep quantum bits in the same physical state up to 10 times longer than before, the report finds.
Silicon dominates in microelectronics and photovoltaics industry, but has been considered unsuitable for light-emitting diodes for a long time. At the nanoscale, however, its properties change. Scientists in Germany and Canada have now succeeded in manufacturing silicon-based light-emitting diodes (SiLEDs) using silicon nanocrystals a few nanometers in size. They are free of heavy metals and can emit light in various colors.
Researchers at North Carolina State University have developed a new type of nanoscale structure that resembles a “nano-shish-kebab,” consisting of multiple 2D nanosheets that appear to be impaled upon a 1D nanowire. However, the nanowire and nanosheets are actually a single, 3D structure consisting of a seamless series of germanium sulfide (GeS) crystals. The structure holds promise for use in the creation of new, 3D technologies.
Stretched-out clothing might not be a great practice for laundry day, but in the case of microprocessor manufacture, stretching out the atomic structure of the silicon in the critical components of a device can be a good way to increase a processor's performance.
Scientists from the U.S. Department of Energy’s National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at the apex of a gallium arsenide-aluminum gallium arsenide core-shell nanowire interface. This activity at optimal locations in nanowires could improve solar cells, quantum computing, and lighting devices.
Researchers have tried for decades to replicate the effects of transistors in transition metal oxides by using a voltage to convert the material from an insulator to a metal, but the induced change only occurs within a few atomic layers of the surface. Recently, however, scientists in Japan have discovered that applying a voltage to a vanadium dioxide film several tens of nanometers thick converts the entire film from an insulator to a metal.
Organic semiconductors hold promise for making low-cost flexible electronics—if they can perform in spite of frequent flexing and sharp bending. Scientists have recently demonstrated extremely flexible organic semiconductors that withstood multiple bending cycles in which the devices were rolled to a radius as small as 200 μm. The scientists worked with numerous crystalline devices they made and found no degradation in their performance.
Silica microwires are the tiny and as-yet underutilized cousins of optical fibers. If precisely manufactured, however, these hair-like slivers of silica could enable applications and technology not currently possible with comparatively bulky optical fiber. By carefully controlling the shape of water droplets with an ultraviolet laser, a team of researchers from Australia and France has found a way to coax silica nanoparticles to self-assemble into much more highly uniform silica wires.
Existing optical beamsteering assemblies for technologies like LADAR, which scans a field of view with a laser to determine distance, are typically mechnical, bulky, slow, and inaccurate. In an effort to design a better, scalable technology, DARPA researchers have recently demonstrated the most complex optical phased array ever built onto a 2D chip.
High-performance infrared cameras are usual for night-vision goggles and are usually either active, which use invisible infrared sources, or passive, which detect thermal radiation without the need for illumination. Integrating both modes has proven challenging, but researchers at Northwestern University have done by using advanced type-II superlattice materials.
A Massachusetts Institute of Technology researcher has developed a technique that provides a new way of manipulating heat, allowing it to be controlled much as light waves can be manipulated by lenses and mirrors. The approach relies on engineered materials consisting of nanostructured semiconductor alloy crystals.
Silicon carbide crystals consist of a regular lattice formed by silicon and carbon atoms. At present, these semiconductors are extensively used in micro and opto-electronics. Physicists have recently modified silicon carbide crystals in a way that these exhibit new and surprising properties. This makes them interesting with regard to the design of high-performance computers or data transmission.
Investigators at the Virginia Tech Carilion Research Institute have invented a way to directly image biological structures at their most fundamental level and in their natural habitats. Their newly developed in situ molecular microscopy provides a gateway to imaging dynamic systems in structural biology
Inductors are essential components of integrated circuits. The sprawling metal spirals store magnetic energy, acting as a buffer against changes in current and modulating frequency. However, because inductance depends on the number of coils, they take up a lot of space. Researchers have recently build a 3D rolled-up inductor with a footprint more than 100 times smaller without sacrificing performance.
After more than a decade of research, chip engineers at IBM Research have built a scalable, fab-ready microchip that successfully integrates a complete optical package built from silicon. This silicon nanophotonics breakthrough allows the new chip, which is built on an existing high-performance 90-nm CMOS fabrication line, to exceed a transceiver data rate of 25 Gbps per channel.
Silicon's crown is under threat: The semiconductor's days as the king of microchips for computers and smart devices could be numbered, thanks to the development of the smallest transistor ever to be built from a rival material, indium gallium arsenide. The compound transistor, built by a team at Massachusetts Institute of Technology, performs well despite being just 22 nm in length.
For the first time, a silicon-based optical fiber with solar cell capabilities has been developed that has been shown to be scalable to many meters in length. The research opens the door to the possibility of weaving together solar cell silicon wires to create flexible, curved, or twisted solar fabrics.
Electronic circuits are typically integrated in rigid silicon wafers, but flexibility opens up a wide range of applications. In a world where electronics are becoming more pervasive, flexibility is a highly desirable trait, but finding materials with the right mix of performance and manufacturing cost remains a challenge. Now a team of researchers from the University of Pennsylvania has shown that nanocrystals of the semiconductor cadmium selenide can be "printed" or "coated" on flexible plastics to form high-performance electronics.