Self-assembled Nanowires Could Make Chips Smaller and Faster
Electrical and computer engineering professor Xiuling Li, left, and graduate research assistant Seth Fortuna have found a new way to make transistors smaller and faster. The technique uses self-assembled, self-aligned, and defect-free nanowire channels made of gallium arsenide. (Photo by L. Brian Stauffer)
Researchers at the University of Illinois have found a new way to make transistors smaller and faster. The technique uses self-assembled, self-aligned, and defect-free nanowire channels made of gallium arsenide.
In a paper to appear in the IEEE (Institute of Electrical and Electronics Engineers) journal Electron Device Letters, U. of I. electrical and computer engineering professor Xiuling Li and graduate research assistant Seth Fortuna describe the first metal-semiconductor field-effect transistor fabricated with a self-assembled, planar gallium-arsenide nanowire channel.
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Mapping Atoms in Nanowire Offers Electronic Nano-Engineering Possibilities
By Emily Ayshford
3D reconstruction of an individual Ge nanowire with each green sphere representing an individual Ge atom. The dimensions are 50x50x100 nm3. The region enclosed by the red box is displayed at upper right, with single atomic planes visible in the center of the image. The grey spheres are phosphorous dopant atoms used to control the conductivity. (The dimensions are 5x25x15 nm3). The region enclosed by the blue box is displayed in the lower right, revealing an inhomogeneous distribution of phosphorous atoms. (The dimensions are 50x50x10 nm3). The 'shell' of enhanced doping results from surface reactions during growth of the nanowire.
Semiconductor nanowires — tiny wires with a diameter as small as a few billionths of a meter — hold promise for devices of the future, both in technology like light-emitting diodes and in new versions of transistors and circuits for next generation of electronics. But in order to utilize the novel properties of nanowires, their composition must be precisely controlled, and researchers must better understand just exactly how the composition is determined by the synthesis conditions.
Nanowires are synthesized from elements that form bulk semiconductors, whose electrical properties are in turn controlled by adding minute amounts of impurities called dopants. The amount of dopant determines the conductivity of the nanowire.
But because nanowires are so small — with diameters ranging from 3 to 100 nanometers — researchers have never been able to see just exactly how much of the dopant gets into the nanowire during synthesis. (more…)
Nanowires May Lead To Better Fuel Cells
A futuristic fuel cell car.
The creation of long platinum nanowires at the University of Rochester could soon lead to the development of commercially viable fuel cells.
Described in a paper published today in the journal Nano Letters, the new wires should provide significant increases in both the longevity and efficiency of fuel cells, which have until now been used largely for such exotic purposes as powering spacecraft. Nanowire enhanced fuel cells could power many types of vehicles, helping reduce the use of petroleum fuels for transportation, according to lead author James C. M. Li, professor of mechanical engineering at the University of Rochester. (more…)
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