Single-Electron Devices

Single-Electron Devices

Directed Self Assembly

Directed self-assembly of the mesoscale system. 10 nm diameter gold nanoparticles coalesce into chains in the presence of salt in solution. The UV-vis absorption spectrum shows a corresponding decrease in absorbed wavelength

I-V Curve

Voltage-current experiment setup and relationship. The current shows the single electron effect at a crititcal voltage. The voltage at which the current rapidly rises decreased with rising temperature.

algea_necklace_experiment"

Photosynthesis coupled single electron transistor: A living Single electron device. The single electron effect of nanoparticle necklace devices is observable in water. Algae can be used as a gate in the single electron transistor device and photosynthesis can be measured.


It is well known for six decades that current through a small metal island does not follow Ohm's law: a threshold bias, VT is needed for current to commence. A single electron can substantially charge the island to block the transport unless adequate bias is applied to overcome the Coulomb Blockade. However, to observe the Coulomb blockade due to single electron charging, the island must be in nanoscale and cryogenic temperatures are required to observe the VT. About a decade ago it was shown that the operating temperature can be raised from 4 K to 150 K in a monolayer array of nanoparticles. The enhancement in the granular system emerges because of the cumulative effect of multiple Coulomb blockades in individual particles (called charge centers) along the percolation path. The theme of our research is to control the defect structure - the location of charge centers and topology of the percolation path, to enhance the synergistic effect in these granular systems to achieve single electron effect at room temperature and subsequently in aqueous media.

Relevent Publications

  • "Self-Assembly of Gold Nanoparticles on Poly(allylamine Hydrochloride) Nanofiber: A New Route to Fabricate "Necklace" as Single Electron Devices", ACS Applied Materials & Interfaces, 2013; 5, 9949-9956.
  • Imaging Electroluminescence from Individual Nanoparticles in an Array Exhibiting Room Temeprature Single Electron Effect, ACS Nano, 2013, 7, 7403-7410.
  • "Single Electron Transistor in Aqueous Media,” Advanced Materials, 2013, 25, 3079-3084. Featured in Nature: News
  • “Self-assembled Nanoparticle Necklaces Network Showing Single-Electron Switching at Room Temperature and Bio-Gating Current by Living Microorganisms,” ACS Nano, 2010, 4, 317-323.