A new approach to integrated circuits, combining atoms of semiconductor materials into nanowires and structures on top of silicon surfaces, shows promise for a new generation of fast, robust electronic and photonic devices.
Engineers at the University of California, Davis, have recently demonstrated three-dimensional nanowire transistors using this approach that open exciting opportunities for integrating other semiconductors, such as gallium nitride, on silicon substrates.
"Silicon can't do everything," said Saif Islam, professor of electrical and computer engineering at UC Davis. Circuits built on conventionally etched silicon have reached their lower size limit, which restricts operation speed and integration density. Additionally, conventional silicon circuits cannot function at temperatures above 250 degrees Celsius (about 480 degrees Fahrenheit), or handle high power or voltages, or optical applications.
The new technology could be used, for example, to build sensors that can operate under high temperatures, for example inside aircraft engines.
"In the foreseeable future, society will be dependent on a variety of sensors and control systems that operate in extreme environments, such as motor vehicles, boats, airplanes, terrestrial oil and ore extraction, rockets, spacecraft, and bodily implants," Islam said.
Devices that include both silicon and nonsilicon materials offer higher speeds and more robust performance. Conventional microcircuits are formed from etched layers of silicon and insulators, but it's difficult to grow nonsilicon materials as layers over silicon because of incompatibilities in crystal structure (or "lattice mismatch") and differences in thermal properties.
Instead, Islam's laboratory at UC Davis has created silicon wafers with "nanopillars" of materials such as gallium arsenide, gallium nitride or indium phosphide on them, and grown tiny nanowire "bridges" between nanopillars.
"We can't grow films of these other materials on silicon, but we can grow them as nanowires," Islam said.
The researchers have been able to make these nanowires operate as transistors, and combine them into more complex circuits as well as devices that are responsive to light. They have developed techniques to control the number of nanowires, their physical characteristics and consistency.
Islam said the suspended structures have other advantages: They are easier to cool and handle thermal expansion better than planar structures — a relevant issue when mismatched materials are combined in a transistor.
The technology also leverages the well-established technology for manufacturing silicon integrated circuits, instead of having to create an entirely new route for manufacturing and distribution, Islam said.
The work is described in a series of recent papers in the journals Advanced Materials, Applied Physics Letters and IEEE Transactions on Nanotechnology with co-authors Jin Yong Oh at UC Davis; Jong-Tae Park, University of Incheon, South Korea; Hyun-June Jang and Won-Ju Cho, Kwangwoon University, South Korea. Funding was provided by the U.S. National Science Foundation and the government of South Korea.
UC Davis is a global community of individuals united to better humanity and our natural world while seeking solutions to some of our most pressing challenges. Located near the California state capital, UC Davis has more than 34,000 students, and the full-time equivalent of 4,100 faculty and other academics and 17,400 staff. The campus has an annual research budget of over $750 million, a comprehensive health system and about two dozen specialized research centers. The university offers interdisciplinary graduate study and 99 undergraduate majors in four colleges and six professional schools.
Andy Fell | Eurek Alert!
Nanobionics Supercharge Photosynthesis
22.05.2015 | Department of Energy, Office of Science
Mesoporous Particles for the Development of Drug Delivery System Safe to Human Bodies
22.05.2015 | National Institute for Materials Science
Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.
Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...
Development and implementation of an advanced automobile parking navigation platform for parking services
To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...
The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...
On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.
RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...
Nanoengineers at the University of California, San Diego developed a gel filled with toxin-absorbing nanosponges that could lead to an effective treatment for skin and wound infections caused by MRSA (methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria. This "nanosponge-hydrogel" minimized the growth of skin lesions on mice infected with MRSA - without the use of antibiotics. The researchers recently published their findings online in Advanced Materials.
To make the nanosponge-hydrogel, the team mixed nanosponges, which are nanoparticles that absorb dangerous toxins produced by MRSA, E. coli and other...
20.05.2015 | Event News
18.05.2015 | Event News
12.05.2015 | Event News
22.05.2015 | Materials Sciences
22.05.2015 | Information Technology
22.05.2015 | Materials Sciences