“We can grow forests of freestanding copper nanowires of controlled diameter and length, suitable for integration into electronic devices,” said Kyekyoon (Kevin) Kim, a professor of electrical and computer engineering.
“The copper nanowires are grown on a variety of surfaces, including glass, metal and plastic by chemical vapor deposition from a precursor,” said Hyungsoo Choi, a research professor in the Micro and Nanotechnology Laboratory and in the department of electrical and computer engineering. “The patented growth process is compatible with contemporary silicon-processing protocols.”
The researchers describe the nanowires, the growth process, and a proof-of-principle field-emission display in a paper accepted for publication in the journal Advanced Materials, and posted on its Web site.
Typically, the nanowires of 70 to 250 nanometers in diameter are grown on a silicon substrate at temperatures of 200 to 300 degrees Celsius and require no seed or catalyst. The size of the nanowires is controlled by the processing conditions, such as substrate, substrate temperature, deposition time and precursor feeding rate. The columnar, five-sided nanowires terminate in sharp, pentagonal tips that facilitate electron emission.
To demonstrate the practicability of the low-temperature growth process, the researchers first grew an array of copper nanowires on a patterned silicon substrate. Then they fashioned a field-emission display based on the array’s bundles of nanowires.
In a field-emission display, electrons emitted from the nanowire tips strike a phosphor coating to produce an image. Because the researchers used a bundle of nanowires for each pixel in their display, the failure of a few nanowires will not ruin the device.
“The emission characteristics of the copper nanowires in our proof-of-principle field-emission display were very good,” said Kim, who also is affiliated with the U. of I.’s department of materials science and engineering, department of bioengineering, department of nuclear, plasma and radiological engineering, Beckman Institute, Micro and Nanotechnology Laboratory, and the Institute for Genomic Biology. “Our experimental results suggest bundled nanowires could lead to longer lasting field-emission displays.”
In addition to working on flexible displays made from copper nanowires grown on bendable plastic, the researchers are also working on silver nanowires.
With Kim and Choi, co-authors of the paper are graduate student and lead author Chang Wook Kim, graduate student Wenhua Gu, postdoctoral research associate Martha Briceno, and professor and head of materials science and engineering Ian Robertson.
Funding was provided by the University of Illinois. Characterization of the samples was conducted at the university’s Center for Microanalysis of Materials, which is partially funded by the U.S. Department of Energy.To reach Kyekyoon Kim, call 217-333-7162; e-mail: email@example.com.
James E. Kloeppel | University of Illinois
A tale of two pulsars' tails: Plumes offer geometry lessons to astronomers
18.01.2017 | Penn State
Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Power and Electrical Engineering
18.01.2017 | Materials Sciences
18.01.2017 | Life Sciences