Photodetectors from DNA

The large molecule deoxyguanosine (DG) is one of four basic units that encode genetic information in DNA. It also turns out to be a good semiconductor material in some experimental photodetectors. Researchers at the National Nanotechnology Laboratory of the National Institute for the Physics of Matter (INFM) in Italy fabricated their detectors by placing a tiny droplet of DG, dissolved in chloroform, at the juncture of two electrodes. As the chloroform evaporated, the DG molecules self-assembled into an array of 100-nm-long ribbons between the electrodes. The resulting DG-based photodetectors are roughly twice as sensitive to light as commercially available detectors. If the researchers can succeed in doubling the length of the DG ribbons to about a quarter of a micron, the chloroform solution could be deposited with a modified inkjet printer nozzle, while the rest of the device could be manufactured in a modern semiconductor lithography facility. The researchers point out that, ultimately, a multitude of electrical components could rely on a surprisingly small number of molecules. (R. Rinaldi et al., Appl. Phys. Lett. 78 , 3541, 2001 http://dx.doi.org/10.1063/1.1374232 .)