IRG-III Nugget
Multi-island single electron device from self-assembled nanocrystals
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Electron microscopy image showing a single electron device comprised of 50 nm gold nanoparticles connecting two electrodes. As dimensions are reduced to the nanoscale, it is possible to observe single electrons as they are transported from the input lead in a device to the output lead. The ability to control currents at the single electron level is fundamental for the creation of new families of ultra-sensitive electronic devices. Single electron devices have in the past been restricted to operating at temperatures below 1 Kelvin because of limitations in lithography. Nanocrystals can reach sizes far below those accessible by lithography. Previous nanocrystal based devices have however focused on either having a single nanocrystal between two leads, or a large number. Here we demonstrate unprecedented control in fabricating a single electron device whose active component is a pair of 50 nm gold nanocrystals (see Figure below). The conductance characteristics of the device show a complex pattern, and analysis of the data shows that all the features can be understood as a result of changing the number of electrons residing on each of the two nanocrystals. This device easily operates at 4 Kelvin. This work, a collaboration between the Kastner and Bawendi groups within the MIT MRSEC, validates self-assembled nanocrystals as building blocks for designing complex single electron devices that have the potential to operate at room temperature.
