DUBLIN, IRELAND-Imagine devices that are liquid-cooled in such an efficient manner that more densely packed circuits are possible in communications networks. With denser packing comes greater processing speeds in a smaller package, and potentially lower-cost broadband services. For scientists at Bell Labs, the research arm of Lucent Technologies, the greener pastures of improved communications networks may be possible thanks to “nanograss” and the initiation of a focused research project on the material to be spearheaded by researchers from Bell Labs’ new laboratory in Blanchardstown, Ireland.
Invented last year by researchers at Bell Labs, nanograss is an engineered silicon surface that resembles a lawn of evenly cut grass. The silicon towers, each about 100 nm in diameter and several microns tall, are packed together with separations of several hundred nm and coated with a non-stick, water-repellant surface material similar to Teflon. This unique geometry allows fluids to move across the top of the material without wetting the surface below; however, a small electrical current can be applied to a localized area of the material allowing the fluid to sink down and wet the surface.
Using the nanograss to transfer heat from silicon surfaces to liquid coolants in order to solve the thermal management challenges of advanced electronic and photonic systems is just one of many applications to be investigated as part of the Lucent Technologies nanograss project. Another application for the materials may be in optical switching. Droplets of fluid on a nanograss surface can alter the physical properties of the transmitting medium through which light signals are sent, possibly enabling a unique optical switching technology or other nano-scale optical components such as filters.
Besides these photonic applications, Tom Krupenkin, the Bell Labs scientist who led the research, cites several other potential applications such as self-cleaning windshields, more streamlined boat hulls due to the water repellant feature of the nanograss, and longer-lasting batteries (by keeping the electrode and the electrolyte separated by an air gap inside the nanograss until the battery is activated). In fact, a nanograss-based battery has already been demonstrated by Bell Labs researchers and scientists from mPhase Technologies (Norwalk, CT), who have announced a joint program to develop and commercialize this technology. The researchers say that modifications to the materials and the geometry of the nanograss are easily accomplished and will further increase the potential applications for the material.
Lucent wants to make it clear that this is still very much a research project and that many technological advances are necessary before commercial applications for nanograss can be realized. The Blanchardstown scientists are collaborating with Bell Labs researchers in Murray Hill, NJ, and with three Irish universities-Trinity College (Dublin, Ireland), the Tyndall Institute of University College Cork (Cork, Ireland), and the University of Limerick (Limerick, Ireland).
These institutions in Ireland offer a skilled group of individuals dedicated to moving technology into commercial arenas, and effectively cooperate as a “best-in-class nanotechnology dream team,” according to Dave Bishop, vice president of nanotechnology research at Bell Labs in Murray Hill, NJ, and president of the New Jersey Nanotechnology Consortium. Bishop is excited about the future of nanograss and notes that the concept of “nano” is certainly not new in the photonics industry.
“Although the term ‘nanotechnology’ is a relatively recent label, one could argue that the photonics industry couldn’t exist today without the ability to pattern and manipulate materials on the nano-scale,” Bishop said.
-Gail Overton