A new low-temperature nanowire growth process can create ultrasensitive UV smoke detectors directly on a microchip. A ZnO nanowire detector created through a seedless hydrothermal technique is 10,000 times more sensitive to UV radiation than traditional ZnO detectors, according to researchers at the University of Surrey. This sensitivity could allow the detector to pick up tiny smoke particles emitted at the early stages of fires. Today’s photoelectric smoke detectors sense larger particles found in dense smoke, but are not as sensitive to small particles from rapidly burning fires. “UV light detectors made from zinc oxide have been used widely for some time, but we have taken the material a step further to massively increase its performance,” said professor Dr. Ravi Silva. “Essentially, we transformed zinc oxide from a flat film to a structure with bristle-like nanowires, increasing surface area and therefore increasing sensitivity and reaction speed.” The device has a response time of 90 ms and recovery time of 210 ms, which the researchers attributed to the nanowire-nanowire junction-barrier-dominated resistance and the direct contact between ZnO and Au electrodes. The nanowire detector approach could have applications from fire and gas sensing to air pollution monitoring, and could be incorporated into smartphones and tablets. “This is a great example of a bespoke, designer nanomaterial that is adaptable to personal needs, yet still affordable,” Silva said. “Due to the way in which this material is manufactured, it is ideally suited for use in future flexible electronics, a hugely exciting area.” The research was published in Scientific Reports (doi: 10.1038/srep08516 [open access]). For more information, visit www.surrey.ac.uk.