One problem in developing more efficient OLED light bulbs and displays for televisions and phones is that much of the light is polarized in one direction and thus trapped within the LED. Univ. of Utah physicists believe they have solved the problem by creating a new organic molecule that is shaped like rotelle—wagon-wheel pasta—rather than spaghetti.
Researchers in Germany are showing the way toward low-cost, industrial-scale manufacturing of a new family of electronic devices. Gas sensors that could be integrated into food packaging to gauge freshness, new types of solar cells and flexible transistors, and sensors that could be built into electronic skin: All can be made with carbon nanotubes, sprayed like ink onto flexible plastic sheets or other substrates.
Anyone who’s stuffed a smartphone in their back pocket would appreciate the convenience of electronic devices that could bend. Alas, electronic components are generally made from stiff and brittle metals and inorganic semiconductors. Now, researchers have created the first theoretical framework seeking to understand, predict and improve the conductivity of semiconducting polymers.
Univ. of Illinois at Urbana-Champaign researchers have developed arrays of tiny nanoantennas that can enable sensing of molecules that resonate in the infrared (IR) spectrum. Other nanoscale antenna systems can't be tuned to a longer light wavelength due to limitations of traditional nanoantenna materials. The team used highly doped semiconductors, grown by molecular beam epitaxy.
A new, environmentally-friendly electronic alloy consisting of 50 aluminum atoms bound to 50 atoms of antimony may be promising for building next-generation "phase-change" memory devices. Phase-change memory is being actively pursued as an alternative to the ubiquitous flash memory for data storage applications, because flash memory is limited in its storage density and phase-change memory can operate much faster.
By inserting platinum atoms into an organic semiconductor, Univ. of Utah physicists were able to “tune” the plastic-like polymer to emit light of different colors—a step toward more efficient, less expensive and truly white organic light-emitting diodes (OLEDs) for light bulbs of the future.
Researchers at North Carolina State Univ. have created a new compound, strontium tin oxide (Sr3SnO) that can be integrated into silicon chips and is a dilute magnetic semiconductor, meaning that it could be used to make “spintronic” devices, which rely on magnetic force to operate, rather than electrical currents.
Researchers in Canada have found that abundant materials in the Earth's crust can be used to make inexpensive and easily manufactured nanoparticle-based solar cells. The team has designed nanoparticles that absorb light and conduct electricity from two very common elements: phosphorus and zinc. These are much more plentiful than scarce cadmium, and safer than lead.
Titanium dioxide is an inexpensive, yet versatile material. The use of titanium oxide in the electronics industry is currently being investigated. An international team of researchers has confirmed theoretically-predicted interactions between single oxygen molecules and crystalline titanium dioxide and the implications of these findings could be important for a variety of applications.
Devices based on gallium arsenide (GaAs) have numerous applications, such as photovoltaics, because it is a wide bandgap semiconductor and can be used under extreme conditions—high-temperature, high-power and high-radiation environments—where conventional silicon-based devices can’t adequately perform. However, GaAs wafers have been expensive, inflexible and limited to 6 in in diameter. TexMat LLC and TapeSolar have introduced a new type of GaAs wafer that is flexible and can be produced in sizes measuring in meters, not inches.
They're not exactly the peanut butter and jelly of semiconductors, but when you put them together, something magical happens. Alone, neither lanthanum aluminate nor strontium titanate exhibit any particularly notable properties. But when they are layered together, they become not only conductive, but also magnetic.
A RMIT Univ. research collaboration with top scientists in Australia and Japan is advancing next-generation solar cells. Currently, cadmium or lead elements dominate colloidal nanocrystals synthesis, despite toxicity concerns. In its research, the team has discovered a new selective synthesis of tetrahedrite and famatinite copper antimony sulphide nanocrystals, which could be promising for printable solar cell applications.
Semiconductor manufacturers look for ways to save wafer material. According to recent research, ultra-thin saws made of carbon nanotubes and coated with diamond would be able to cut through silicon wafers with minimum loss. A new method that grows both nanotubes and diamonds makes it possible to manufacture the saw wires.
Many of today’s semiconductor technologies hinge upon the absorption of light. Absorption is critical for nano-sized structures at the interface between two energy barriers called quantum wells, in which the movement of charge carriers is confined to two dimensions. Working with the semiconductor indium arsenide, a team of researchers has discovered a quantum unit of photon absorption that should be general to all 2-D semiconductors.
From solar cells to opto-electronic sensors to lasers and imaging devices, many of today’s semiconductor technologies hinge upon the absorption of light. Absorption is especially critical for nano-sized structures at the interface between two energy barriers called quantum wells. Now, for the first time, a simple law of light absorption for 2-D semiconductors has been demonstrated.
A collaboration of scientists from the Univ. of Minnesota and the National Renewable Energy Laboratory have developed a new method to use an ionized gas, called nonthermal plasma, to produce silicon nanocrystals and cover their surfaces with a layer of chlorine atoms. This method allows production of stable silicon inks without organic ligand molecules and also greatly enhances conductivity.
Combining experiment and theory, Cornell Univ. researchers have shown that when grown in stacked layers, graphene produces some specific defects that influence its conductivity. Previously it was thought that when perfectly stacked in layers, graphene would be defect-free. Instead, it ripples. The finding could influence efforts to make graphene act like a semiconductor.
Andrew Greytak, a chemist at the University of South Carolina, is leading a research team that’s making the process of synthesizing quantum dots much more systematic. His group recently detailed an effective new method for purifying cadmium selenide nanocrystals with well-defined surface properties. The advance required the adoption of gel-permeation chromatography.
A team led by Rice University chemist James Tour has built a 1-kilobit rewritable device with diodes that eliminate data-corrupting crosstalk. This chip, which uses cheap, plentiful silicon oxide to store data, shows it should be possible to surpass the limitations of flash memory in packing density, energy consumption per bit and switching speed.
An unlikely material, cubic boron arsenide, could deliver an extraordinarily high thermal conductivity—on par with the industry standard set by costly diamond. The discovery that the chemical compound of boron and arsenic could rival diamond surprised the team of theoretical physicists. But a new theoretical approach allowed the team to unlock the secret to boron arsenide's potentially extraordinary ability to conduct heat.
In the constant push for smaller transistors, researchers have been investigating oxides with higher K, or dielectric constant, values. Materials such as germanium, hafnium, and titanium are being investigated for this role, but many prototypes leak electrons. At the National Synchrotron Light Source, x-rays are being used to probe the electronic behavior of a germanium-based transistor structure that could offer a solution.
Researchers in Switzerland have designed prototype for an image sensor based on the semiconducting properties of molybdenite. Their sensor only has a single pixel, but it needs five times less light to trigger a charge transfer than the silicon-based sensors that are currently available.
Through-focus scanning optical microscopy, a technique developed several years ago at NIST for improving optical microscopes, now has been applied to monitoring the next generation of computer chip circuit components, potentially providing the semiconductor industry with a crucial tool for improving chips for the next decade or more.
The world’s most advanced extreme-ultraviolet microscope is about to go online at Lawrence Berkeley National Laboratory, and the queue of semiconductor companies waiting to use it already stretches out the door. The much-anticipated SHARP microscope will provide semiconductor companies with the means to push their chip-making technology to new levels of miniaturization and complexity.
At the IEEE Photovoltaic Specialists Conference in Tampa, Fla. last week, National Renewable Energy Laboratory scientist Myles Steiner announced a world record of 31.1% conversion efficiency for a two-junction solar cell under one sun of illumination. The achievement edges the previous record of 30.8% by Alta Devices.