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Smallest Quantum Dots Ever Created

Date:
January 28, 2009
Source:
University of Alberta
Summary:
Single atom quantum dots make possible a new level of control over individual electrons, a development that suddenly brings quantum dot-based devices within reach. Composed of a single atom of silicon and measuring less than one nanometer in diameter, these are the smallest quantum dots ever created.
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2 coupled atomic quantum dots are shown in this room temperature scanning tunneling microscopy image. In the top frame the dots share one electron. The electron moves freely between the dots just like an electron in a chemical bond within a molecule. The lower frame demonstrates control over that single electron and the potential to do computations in a new way. The electric field from the control charge pushes the electron to prefer staying on only one of the quantum dots.
Credit: Image courtesy of University of Alberta/Prof. Robert A. Wolkow

Single atom quantum dots created by researchers at Canada’s National Institute for Nanotechnology and the University of Alberta make possible a new level of control over individual electrons, a development that suddenly brings quantum dot-based devices within reach. 

Composed of a single atom of silicon and measuring less than one nanometre in diameter, these are the smallest quantum dots ever created. 

Quantum dots have extraordinary electronic properties, like the ability to bottle-up normally slippery and speedy electrons.  This allows controlled interactions among electrons to be put to use to do computations. Until now, quantum dots have been useable only at impractically low temperatures, but the new atom-sized quantum dots perform at room temperature.

Often referred to as artificial atoms, quantum dots have previously ranged in size from 2-10 nanometers in diameter.  While typically composed of several thousand atoms, all the atoms pool their electrons to “sing with one voice”, that is, the electrons are shared and coordinated as if there is only one atomic nucleus at the centre.  That property enables numerous revolutionary schemes for electronic devices.

Research project leader Robert A. Wolkow described the potential impact saying, “Because they operate at room temperature and exist on the familiar silicon crystals used in today’s computers, we expect these single atom quantum dots will transform theoretical plans into real devices.”

The single atom quantum dots have also demonstrated another advantage – significant control over individual electrons by using very little energy.  Wolkow sees this low energy control as the key to quantum dot application in entirely new forms of silicon-based electronic devices, such as ultra low power computers.  “The capacity to compose these quantum dots on silicon, the most established electronic material, and to achieve control over electron placement among dots at room temperature puts new kinds of extremely low energy computation devices within reach.”


Story Source:

The above story is based on materials provided by University of Alberta. Note: Materials may be edited for content and length.


Journal Reference:

  1. M Baseer Haider, M. Baseer Haider, Jason L Pitters, Gino A. DiLabio, Lucian Livadaru, Josh Y Mutus and Robert A. Wolkow. Controlled Coupling and Occupation of Silicon Atomic Quantum Dots at Room Temperature. Physical Review Letters, January 27, 2009 DOI: 10.1103/PhysRevLett.102.046805

Cite This Page:

University of Alberta. "Smallest Quantum Dots Ever Created." ScienceDaily. ScienceDaily, 28 January 2009. <www.sciencedaily.com/releases/2009/01/090127170710.htm>.
University of Alberta. (2009, January 28). Smallest Quantum Dots Ever Created. ScienceDaily. Retrieved May 29, 2015 from www.sciencedaily.com/releases/2009/01/090127170710.htm
University of Alberta. "Smallest Quantum Dots Ever Created." ScienceDaily. www.sciencedaily.com/releases/2009/01/090127170710.htm (accessed May 29, 2015).

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