Research Fellows Directory
Professor Arokia Nathan BSc PhD
University College London
Current research in silicon technology is beginning to dramatically translate what has been viewed as science fiction to reality. Examples range from flexible electronic plastic for creation and display of human size digital x-ray images to energy conversion devices that are free of form factor. A driving force in this evolution lies in the ability to layer silicon on mechanically flexible substrates, which include plastic, metal foils, polyester, and ultimately paper. Interests in this non-conventional family of substrates is being driven by the need for: lightweight, unbreakable, and foldable screens for e-book displays and bio-imaging arrays; large solid angle electronic “eyes” for high optical coupling; and low cost roll-to-roll energy conversion devices. Although there are other competing material families based on organic systems, our immediate research objectives will evolve around silicon given its maturity and low cost. The proposed research program addresses the development of sub-150°C nano-crystalline silicon (nc-Si) deposition technology, and associated building blocks for nc-Si electronics on plastic for imaging and display applications. The technology underlying both image acquisition and display of information is similar. In imaging, a device captures radiant energy such as visible light or x-rays and converts it to an electrical current. For display applications, the opposite occurs, in which electrical energy is transformed into light. In both cases, the technical challenge lies in creating sensors, actuators, and thin film transistor circuits at low temperature. These are currently fabricated at 300-400°C on glass substrates. Plastic, however, loses its essential physical properties at this temperature. Therefore we need to overcome the major technical challenges in basic science underpinning thin film technology, to make devices and circuits work at 150°C or lower temperatures, without compromising the electrical integrity.