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New Connection between Stacked Solar Cells Can Handle Energy of 70,000 Suns

By Guest PostSeptember 25, 2013Scienceconversion efficiency, energy, gallium arsenide, geoff bradshaw, heat, jeff harmon, joshua samberg, new technique, north Carolina, photovoltaic energy, salah bedair, solar energy, stacked solar cells, state university, suns, thin film, voltage, wasted energy, zachary carlin

North Carolina State University researchers have come up with a new technique for improving the connections between stacked solar cells, which should improve the overall efficiency of solar energy devices and reduce the cost of solar energy production. The new connections can allow these cells to operate at solar concentrations of 70,000 suns worth of energy without losing much voltage as “wasted energy” or heat.

Stacked solar cells consist of several solar cells that are stacked on top of one another. Stacked cells are currently the most efficient cells on the market, converting up to 45 percent of the solar energy they absorb into electricity. (more…)

Researchers Solve Riddle of What Has Been Holding Two Unlikely Materials Together

By Guest PostMarch 23, 2013Sciencebi2te3, bismuth telluride, bonds, electricity, electronics, gaas, gallium arsenide, heat into electricity, houston dycus, james lebeau, jonathan pierce, molecules, north Carolina, rama venkatasubramanian, rti international, state university, super x, thin films, van der waals, weak electrical forces

For years, researchers have developed thin films of bismuth telluride (Bi2Te3) – which converts heat into electricity or electricity to cooling – on top of gallium arsenide (GaAs) to create cooling devices for electronics. But while they knew it could be done, it was not clear how – because the atomic structures of those unlikely pair of materials do not appear to be compatible. Now researchers from North Carolina State University and RTI International have solved the mystery, opening the door to new research in the field.

“We’ve used state-of-the-art technology to solve a mystery that has been around for years,” says Dr. James LeBeau, an assistant professor of materials science and engineering at NC State and co-author of a paper on the research. “And now that we know what is going on, we can pursue research to fine-tune the interface of these materials to develop more efficient mechanisms for converting electricity to cooling or heat into electricity. Ultimately, this could have applications in a wide range of electronic devices.” (more…)

Another Advance on the Road to Spintronics

By Guest PostOctober 21, 2012Sciencealbert einstein, alexander gray, analyzer, basis, berkeley lab, charles fadley, computing industry, contamination, data, dilute, electron, electronic structure, energy conversion, energy-efficient, exchange model, facility, ferromagnetic, gallium arsenide, gallium atom, gamnas, harpes, hyogo, jan minar, Japan, jun fujii, kelvin, magnetic atom, magnetic semiconductor, memory architecture, nanoscale device, new technique, p d, peter stone, photoelectric effect, photoemission, photovoltaic cell, processing, room temperature, shigenori ueda, spin, spintronic application, spintronic technology, spring8, storage, surface reaction, synchrotron radiation, xray angle, yoshiyuki yamashita

Berkeley Lab Researchers Unlock Ferromagnetic Secrets of Promising Materials

Spintronic technology, in which data is processed on the basis of electron “spin” rather than charge, promises to revolutionize the computing industry with smaller, faster and more energy efficient data storage and processing. Materials drawing a lot of attention for spintronic applications are dilute magnetic semiconductors – normal semiconductors to which a small amount of magnetic atoms is added to make them ferromagnetic. Understanding the source of ferromagnetism in dilute magnetic semiconductors has been a major road-block impeding their further development and use in spintronics. Now a significant step to removing this road-block has been taken.

A multi-institutional collaboration of researchers led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), using a new technique called HARPES, for Hard x-ray Angle-Resolved PhotoEmission Spectroscopy, has investigated the bulk electronic structure of the prototypical dilute magnetic semiconductor gallium manganese arsenide. Their findings show that the material’s ferromagnetism arises from both of the two different mechanisms that have been proposed to explain it. (more…)

Solving a Spintronic Mystery:

By Guest PostFebruary 29, 2012Scienceberkeley lab, charge carriers, curie temperature, electron acceptors, electronic states, fermi level, ferromagnetic properties, gallium, gallium arsenide, gallium manganese arsenide, jacek furdyna, kin man yu, magneto optical data, margaret dobrowolska, mona berciu, rutherford backscattering facility, semiconductor, silicon, spin, spintronic devices, spintronic potential, spintronic technology, university of notre dame, valence energy band, wladek walukiewicz, xinyu liu

*Berkeley Lab Researchers Resolve Controversy Over Gallium Manganese Arsenide that Could Boost Spintronic Performance*

A long-standing controversy regarding the semiconductor gallium manganese arsenide, one of the most promising materials for spintronic technology, looks to have been resolved. Researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) in collaboration with scientist from University of Notre Dame have determined the origin of the charge-carriers responsible for the ferromagnetic properties that make gallium manganese arsenide such a hot commodity for spintronic devices. Such devices utilize electron spin rather than charge to read and write data, resulting in smaller, faster and much cheaper data storage and processing. (more…)

Scientists Build the World’s First Anti-laser

By Guest PostFebruary 20, 2011Scienceanti-laser, coherent light-light waves, gain medium, gallium arsenide, loss medium, near-infrared radiation, optical computing, scientific papers, yale university

More than 50 years after the invention of the laser, scientists at Yale University have built the world’s first anti-laser, in which incoming beams of light interfere with one another in such a way as to perfectly cancel each other out. The discovery could pave the way for a number of novel technologies with applications in everything from optical computing to radiology.

Conventional lasers, which were first invented in 1960, use a so-called “gain medium,” usually a semiconductor like gallium arsenide, to produce a focused beam of coherent light-light waves with the same frequency and amplitude that are in step with one another. (more…)

Tag Archives: gallium arsenide

New Connection between Stacked Solar Cells Can Handle Energy of 70,000 Suns

Researchers Solve Riddle of What Has Been Holding Two Unlikely Materials Together

Another Advance on the Road to Spintronics

Solving a Spintronic Mystery:

Scientists Build the World’s First Anti-laser