Bell Labs Scientists Usher in New Era of Molecular-Scale Electronics; Tiny Organic Transistors May Lead to Less Expensive and More Powerful Chips.

Business Editors/High Tech Writers

MURRAY HILL, N.J.--(BUSINESS WIRE)--Oct. 17, 2001

Scientists from Lucent Technologies' (NYSE: LU) Bell Labs have created organic transistors with a single-molecule channel length, setting the stage for a new class of high-speed, inexpensive carbon-based electronics.

The size of a transistor's channel -- the space between its electrodes -- influences its output current and switching speed.

In these new molecular-scale transistors, fabricated by a multidisciplinary team of Bell Labs researchers, the length of one molecule defines the channel's physical dimension; it is more than a factor of ten smaller than anything that has been demonstrated even with the most advanced lithography techniques.

The breakthrough is reported in the October 18th issue of the journal Nature.

Scientists have been looking for alternatives to conventional silicon electronics for many years, because they anticipate that the continuing miniaturization of silicon-based integrated circuits will subside in approximately a decade as fundamental physical limits are reached. Some of this research has been aimed at producing molecular-scale transistors, in which single molecules are responsible for the transistor action - switching and amplifying electrical signals.

Bell Labs scientists Hendrik Schon, Zhenan Bao and Hong Meng have now succeeded in fabricating molecular-scale transistors that rival conventional silicon transistors in performance, using a class of organic (carbon-based) semiconductor material known as thiols. "When we tested them, they behaved extremely well as both amplifiers and switches," said Schon, an experimental physicist who was the lead researcher.

Using the tiny transistors, which are roughly a million times smaller than a grain of sand, the team built a voltage inverter, a standard electronic circuit module, commonly used in computer chips, that converts a "0" to a "1" or vice versa. Though just a prototype, the success of the simple circuit suggests that molecular-scale transistors could one day be used in microprocessors and memory chips, squeezing thousands of times as many transistors onto each chip than is possible today.

The main challenges in making molecular-scale transistors are fabricating electrodes that are separated by only a few molecules and attaching electrical contacts to the tiny devices. The Bell Labs researchers were able to overcome these hurdles by using a self-assembly technique and a clever design in which each electrode is shared by many transistors. "We solved the contact problem by letting one layer of organic molecules self-assemble on one electrode first, and then placing the second electrode above it," said Bao, an organic chemist. "For the self assembly, we simply make a solution of the organic semiconductor, pour it on the base, and the molecules do the work of finding the electrodes and attaching themselves."

"This is a beautiful, simple and clever approach," said Professor Paul Weiss of the Pennsylvania State University, an expert in molecular electronics. "It circumvents many of the difficulties inherent in other nanofabrication approaches."

The chemical self-assembly technique is relatively easy and inexpensive, but is key to reducing the transistor's channel length. The channel length of the experimental transistors is between one and two nanometers (billionths of a meter), an order of magnitude smaller than any transistor channel created before.

Bell Labs' transistor legacy

Bell Labs has a long and illustrious connection with transistors. William Shockley, John Bardeen and Walter Brattain invented the transistor at Bell Labs in 1947. Their invention spawned the digital age and earned them the Nobel Prize for Physics in 1956. Over the years, Bell Labs scientists have made many of the important contributions that have helped make transistors smaller, faster and more powerful. The technology curve has culminated with the latest development of molecular-scale transistors.

"The molecular-scale transistors that we have developed may very well serve as the historical 'bookend' to the transistor legacy started by Bell Labs in 1947," said Federico Capasso, physical research vice president at Bell Labs.

With approximately 16,000 employees in 16 countries, Bell Labs is the leading source of new communications technologies. Bell Labs has generated more than 28,000 patents since 1925 and has played a pivotal role in inventing or perfecting key communications technologies, including transistors, digital networking and signal processing, lasers and fiber-optic communications systems, communications satellites, cellular telephony, electronic switching of calls, touch-tone dialing, and modems. Bell Labs scientists have received six Nobel Prizes in Physics, nine U.S. Medals of Science and six U.S. Medals of Technology. For more information about Bell Labs, visit its Web site at http://www.bell-labs.com.

Lucent Technologies, headquartered in Murray Hill, N.J., USA, designs and delivers networks for the world's largest communications service providers. Backed by Bell Labs research and development, Lucent relies on its strengths in mobility, optical, data and voice networking technologies as well as software and services to develop next-generation networks. The company's systems, services and software are designed to help customers quickly deploy and better manage their networks and create new, revenue-generating services that help businesses and consumers. For more information on Lucent Technologies, visit its Web site at http://www.lucent.com .

NOTE TO REPORTERS AND EDITORS:

In conjunction with this announcement, Bell Labs will organize an audiocast and webcast for journalists on Wednesday, October 17, 2001 at 3:00 p.m. Eastern time. Hendrik Schon, the project's lead researcher, and John Rogers, director of nanotechnology research at Bell Labs, will discuss the results and answer questions.

To participate in the audiocast, please call the appropriate number given below.

Within the U.S.: 800-677-1859

Outside the U.S.: 706-645-9790

Please use access code: 2066663

To ask a question during the audiocast, press "1" on the audio bridge.

For audio bridge help, please call [phone] or [phone]

URLs for webcast: http://www.lucent.com/pressroom/webcast

High-resolution downloadable images will be available at http://www.bell-labs.com, starting 2:00 p.m. US ET on October 17, 2001.