Energy lost as heat during the production of electricity could be harnessed through silicon nanowires synthesized via a technique developed at the U.S. Department of Energy's Lawrence Berkeley National Laboratory and the University of California at Berkeley. Scientists believe the technology could produce massive savings on fuel and carbon dioxide emissions.
The electroless etching method involves synthesizing arrays of silicon nanowires in an aqueous solution, on wafers up to dozens of square inches in area. The vertically-aligned silicon nanowires feature exceptionally rough surfaces -- believed to be critical to their high thermoelectric efficiency. "The rough surfaces are definitely playing a role in reducing the thermal conductivity of the silicon nanowires by a hundredfold, but at this time we don't fully understand the physics," said Arun Majumdar, director of Berkeley Lab's Environmental Energy Technologies Division and one of the project's principal researchers.
Majumdar and other researchers envision the thermoelectric materials being used to capture much of the low-grade waste heat now being lost and convert it back to electricity. The scientists are focusing research efforts on fabricating thermoelectric modules based on the silicon nanowire arrays.