Getting it done

Organic electronics R and D requires a different set of lab skills from silicon or III­V work. Just to do the fundamental research takes expertise in organic chemical synthesis, novel manufacturing techniques, and device physics. Sometimes more than one company is needed to put all that together. In one collaboration, PARC does device physics, Motorola (13) does the manufacturing, and Dow Chemical (65) and the Xerox Research Centre of Canada handle the organic chemistry.

It's rare to find all the needed expertise in one company, but Bell Laboratories (Murray Hill, N.J.) is one of those rarities. It is regarded as the crown jewel of corporate parent Lucent Technologies (17). The lab is historically strong in both chemistry and device physics, and the ease with which cross-fertilization happens there allowed this research to take off.

In the early 1990s, when Bell Labs' organic electronics research was begun by organic chemist Howard E. Katz and electronics engineer Ananth Dodabalapur, the first was a hardcore chemist and the second a self-described "device guy." But both say they have since met in the middle. Dodabalapur, now a professor at the University of Texas at Austin, even supervises chemistry students there. "People at Bell Labs don't draw rigid lines between disciplines," he says. And the space between traditional disciplines has proven fertile ground in the last decade. He and John A. Rogers, who joined the research there in 1997, credit Bell Labs' open structure with the success of the project. The scientists themselves, rather than management, establish projects, and collaborations form spontaneously.

The lab has produced a number of breakthroughs in organic electronics. Among these are useful n-type organic semiconductors, complementary circuits, and plastic-backed active-matrix organic display backplanes (arrays of transistors that drive the pixels of displays). Several firms, including Plastic Logic Ltd. and Royal Philips Electronics (24), have identified plastic backplanes as a major market opportunity and made them a development target. Backplanes for current active-matrix displays use heavy, rigid glass substrates to support their amorphous-silicon thin-film transistors (TFTs). Plastic would be a better substrate, because it is light, bendable, and rugged. But standard amorphous-silicon processing requires temperatures that would melt most plastic.

Conveniently, many organic semiconductors are quite like amorphous silicon with regard to the mobilities of their charge carriers. The speeds with which electrons and holes flit through the semiconductor are the main factor limiting how fast a TFT switches. More importantly, organic materials are flexible, the processes used to deposit them and build them into circuits don't need temperatures above about 100° C, and they lend themselves to large-area manufacturing techniques, some borrowed from the printing industry.