PORTLAND, Ore. -- Amorphous, poly- and crystalline silicon differ in the organization of their atomic lattices; the more organized, the higher the performance. Epitaxial silicon, with its perfect crystalline lattices, is required for high-end chips. Until now, such performance was unavailable for organic semiconductors.
Researchers at the Energy Department's Oak Ridge National Laboratory claim to have demonstrated epitaxial growth in polymers, foreshadowing a plastic chip process that could combine the high speed of silicon with the low cost of plastic.
The conductive polymer called Pedot (polythiophene) is already widely used in LEDs, displays and solar cells, but not in a crystalline form. Oak Ridge researchers said demonstrating epitaxial growth of Pedot will lead to improved, inexpensive organic semiconductors with much better energy efficiency and performance.
To create its epitaxial Pedot, the researchers patterned a crystalline copper surface. The copper template enforced the perfect alignment of the Pedot atoms on the template. After a first seed layer was formed, the subsequent layers grew perfectly above them. The researchers predicted that the technique also could be applied to other organic semiconductors.