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January 27, 2009

Single Atom Silicon Atomic Quantum Dots at Room Temperature


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.

It is demonstrated that the silicon atom dangling bond (DB) state serves as a quantum dot. Coulomb repulsion causes DBs separated by 2 nm to exhibit reduced localized charge, which enables electron tunnel coupling of DBs. Scanning tunneling microscopy measurements and theoretical modeling reveal that fabrication geometry of multi-DB assemblies determines net occupation and tunnel coupling strength among dots. Electron occupation of DB assemblies can be controlled at room temperature. Electrostatic control over charge distribution within assemblies is demonstrated.

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.”





FURTHER READING

Abstract of the University of Alberta paper

Zyves is working with a grant to develop large volume atomically precise quantum dots

Zyvex Labs today announced the award of a $9.7M program funded by DARPA (Defense Advanced Research Projects Agency) and Texas' ETF (Emerging Technology Fund). The goal of this effort is to develop a new manufacturing technique that enables "Tip-Based Nanofabrication" to accelerate the transition of nanotechnology from the laboratory to commercial products. Starting with the construction of 'one-at-a-time' atomically precise silicon structures, the Consortium initially plans to develop atomically precise, 'quantum dot' nanotech-based products in volume at practical production rates and costs.


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