HOUSTON, Sept. 7, 2007 -- A new fabrication technique called nanopantography can create billions of carbon nanotubes in hours and could help popularize a technology that renders LCDs obsolete.
Professors Vincent Donnelly, Demetre Economou and Paul Ruchhoeft, all of the Cullen College of Engineering at the University of Houston (UH), created the new nanofabrication technique that can mass-produce an ordered array of carbon nanotubes -- the most efficient electron emitters known -- by removing some of the largest practical barriers to creating large quantities of nanotech devices, said Economou.
The ability to quickly fabricate massive numbers of carbon nanotubes could enable the display industry to move away from LCDs and toward the superior technology of field emission display (FED), which requires many carbon nanotubes to create a picture with higher resolution than an LCD, the researchers said.
Nanopantography uses standard photolithography to selectively remove parts of a thin film and etching to create arrays of ion-focusing microlenses -- small round holes through a metal structure -- on a substrate, such as a silicon wafer.
“These lenses act as focusing elements,” Donnelly said. “They focus the beamlets to fabricate a hole 100 times smaller than the lens size.”
A beam of ions is then directed at the substrate. When the wafer is tilted, the desired pattern is replicated simultaneously in billions of many closely spaced holes over an area, limited only by the size of the ion beam.
“The nanostructures that you can form out of that focusing can be written simultaneously over the whole wafer in predetermined positions,” Economou said. “Without our technique, nanotech devices can be made with electron-beam writing or with a scanning tunneling microscope. However, the throughput, or fabrication speed, is extremely slow and is not suitable for mass production or for producing nanostructures of any desired shape and material.”
With the right ions and gaseous elements, the nanotech fabrication method can be used to etch a variety of materials and virtually any shape with nanosize dimensions. A standard printing technique that can create lenses measuring 100 nanometers wide could be used to draw features just one nanometer wide if combined with nanopantography.
“We expect nanopantography to become a viable method for rapid, large-scale fabrication,” Donnelly said.
Economou, Donnelly and Ruchhoeft have been working on the technology for four years and UH filed a patent application in December 2006. They hope the technology can become commercially available in five to 10 years and expect it to become a viable method for large-scale production.
For more information, visit: www.uh.edu
- The engraving of a surface by acid, acid fumes or a tool; a process extensively used in the manufacture of reticles.
- field emission display
- An X-Y electrically addressable series of arrays with individual electron emitters bombarding a phosphor-coated transparent plate. The phosphor is induced into luminescence, similar to traditional cathode ray tubes.
- A lithographic technique using an image produced by photography for printing on a print-nonprint, sectioned surface.
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
- thin film
- A thin layer of a substance deposited on an insulating base in a vacuum by a microelectronic process. Thin films are most commonly used for antireflection, achromatic beamsplitters, color filters, narrow passband filters, semitransparent mirrors, heat control filters, high reflectivity mirrors, polarizers and reflection filters.
- A cross-sectional slice cut from an ingot of either single-crystal, fused, polycrystalline or amorphous material that has refined surfaces either lapped or polished. Wafers are used either as substrates for electronic device manufacturing or as optics. Typically, they are made of silicon, quartz, gallium arsenide or indium phosphide.
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