LCD displays could soon be obsolete

Breakthrough paves way for field emission displays

Robert Jaques, vnunet.com 05 Sep 2007

Liquid crystal display (LCD) televisions could soon become obsolete thanks to a new scientific breakthrough by US boffins.

Professors Vincent Donnelly, Demetre Economou and Paul Ruchhoeft, of the Cullen College of Engineering at the University of Houston, have developed a technique that allows certain nanotech devices to be mass-produced.

They believe that this could move the television industry away from the LCD display to the superior field emission display.

Field emission displays use a large array of carbon nanotubes, the most efficient emitters known, to create a higher resolution picture than an LCD.

The breakthrough 'nanopantography' fabrication technique can mass-produce an ordered array of carbon nanotubes and make field emission display fabrication viable.

The method uses standard photolithography to selectively remove parts of a thin film, and etching to create arrays of ion-focusing micro-lenses (small round holes through a metal structure) on a substrate such as a silicon wafer.

"These lenses focus the 'beamlets' to fabricate a hole 100 times smaller than the lens size," Professor Donnelly explained.

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," said Professor Economou.

"Without our technique, nanotech devices can be made with electron-beam writing or with a scanning tunnelling 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.

"We expect nanopantography to become a viable method for rapid, large-scale fabrication."

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