Compared to conventional microcantilever-based explosives detectors, the latest from Oak Ridge National Laboratory is more compact and boasts greater specificity to explosives. The new sensor, the subject of a paper that appears in the Oct. 2 issue of Nature, is based on a silicon platform with an integrated piezoresistor, an embedded heating element. Applying a tiny amount of voltage to the piezoresistor causes mini explosions if an explosive such as TNT is present. The microcantilever bending due to nanoexplosions is detected by a piezoelectric coating on the cantilever. The sensor, being developed by a team led by Thomas Thundat of ORNL and Jesse Adams of the University of Nevada at Reno, overcomes a number of limitations associated with conventional microcantilever sensors. "Our new sensing platform uses integrated elements on each cantilever, reduces power requirements by a factor of 10,000 and allows for an array structure that simplifies the simultaneous use of many cantilevers," said ORNL's Lal Pinnaduwage, the lead author of the paper.
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