DNA part makes transistor

Researchers from the University of Lecce in Italy and the University of Bologna in Italy have produced a transistor made from a derivative of one of the four bases that make up DNA.

The field-effect transistor, which carries electricity from a source electrode to a drain electrode when turned on by a gate electrode, is made from a group of guanosine bases the researchers coaxed to self-assemble into orderly ribbons. The researchers used beams of electrons to etch metal electrodes 20 nanometers apart. They then coaxed a layer of guanosine to form between the electrodes.

The researchers measured a maximum voltage gain of 0.76 for their tiny transistor, which is relatively high for a molecular device, though low compared to standard transistors. Gain is critical for keeping signals from fading. The transistor also operates well at room temperature.

The device, at a few hundred nanometers, is close to the size of today's silicon transistors. The self-assembling nature of the molecular layer means guanosine-based transistors could be manufactured in large numbers at low cost, according to the researchers.

The researchers are working on improving the device's electrical properties and long-term stability.

The work appeared in the April 9, 2003 issue of Nano Letters.