Towards DNA-based single electron electronics

We have demonstrated a method to fabricate single electron transistor (SET) by utilizing the molecule of toppari2.jpgthe heritage, i.e. DNA, and its unique self-assembly properties [1]. The DNA itself is not taking part to the actual electrical function, but acts as a scaffold to organize a linear, pearl necklace like nanostruc­ture consisting of three gold nanoparticles (AuNP) as shown in Figure right. The whole process is based on DNA self-assembly, and thus yields countless of structures within a single patch.

The nature of electrical conduction in nanoscale materials differs vastly from macroscale structures having countless electrons forming the current. For example, addition of even a single electron into a nanosized piece of metal can increase its energy enough to prevent further conduction through it. Devices based on this phenomenon, i.e., single electron devices, have been fabricated within the scale of tens of nanometers by conventional micro- and nanofabrication methods for some time now. However, the weakness of these structures has been the cryogenic temperatures needed for them to work. The operation temperature scales up as the size of the component decreases. The ultimate aim is to have the devices working at room temperature, which is hardly possible by conventional nanofabrication methods. However, as shown here – metallic nanoparticles with the size of only few nanometers together with DNA based self-assembly – offer a very suitable toolkit for this purpose [1].

After fabrication, we trapped our self-assembled structures by dielectrophoresis between firgertip-type gold nanoelectrodes and measured its IV-characteristics. We observed clear Coulomb blockade (see inset in Figure 1), which is essential for SET operation, all the way up to room temperature. This demonstrates for the first time that this kind of scalable fabrication methods based on DNA self-assembly can be efficiently utilized to fabricate single electron devices functioning at room temperature.