Organic Chips: Lasers Not Health Food

By Dan Whipple  |  Posted 2001-02-12

Breakthroughs in the physics of transistors may eventually permit them to be manufactured like rubber stamps, dramatically reducing the cost and investment required for silicon chip production.

But not soon.

Scientists have looked for years for replacements for the inorganic materials typically used in transistors. Physicists at Lucent Technologies Bell Labs recently announced breakthroughs in the development of "light-emitting, field effect transistors" — lasers — made from organic materials they say are easier and less costly to manufacture than inorganic compounds.

Small electric lasers guide powerful beams of light for many uses, including CD players, laser printers, surgical equipment and telecommunications equipment.

"Previously, researchers in the laser community thought organic materials would never be able to carry the large current necessary for electrically powered organic lasers," says Bertram Batlogg, head of Bell Labs solid state physics research department, who collaborated with Christian Kloc, Hendrik Schön and Ananth Dodabalapur on the research.

To make the organic lasers, Kloc and colleagues grew high-quality crystals of tetracene, an organic substance the molecules of which contain four connected benzene rings that conduct electricity well. When the researchers excited the tetracene crystals with electric current, light bounced back and forth between facets — or mirrors — in the crystals and eventually produced beams of intense light.

"We hope now that we can implement this kind of technology to achieve arrays of organic lasers and lasers of different colors," says Bell Labs physicist Schön. "Potential applications would be in laser printing, optical storage and such kinds of technology."

The next step, Schön said, "would be to deposit films on flexible substrates and make thin film devices to achieve vertical imaging lasers. Organic materials have advantages in respect to processing. You dont need very high temperatures and complicated systems to deposit them."

But Saswato Das, media-relations manager at Bell Labs, stresses that the organic transistors arent yet ready to compete with gallium arsenide chips.

Still, Das says, "they would be cheap to manufacture and would be particularly useful in certain high-volume applications. Potential uses include roll-up computer screens, smart cards, luggage tags that help airport personnel locate lost suitcases, and tags on groceries that verify whether they were transported under the right conditions to the supermarket."

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