Single electron transistor

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Energy states of a SET in blocking and transmission

As single-electron transistors , including single-electron transistors ( SET for English tunneling single electron or English single electron transistor ) refers to electronic components , which at any given time only a respective one electron can be passed.

The first SET was realized in 1987 at Bell Laboratories by Gerald Dolan and Theodore A. Fulton . Dmitri Averin and Konstantin Likharev made suggestions in 1985.

functionality

Realization of a single electron transistor with Nb-AlO x -Al tunnel junctions. Left: scanning electron microscope image, right: interpretation

Similar to field effect transistors , they have reservoirs called source and drain, as well as (at least) one gate with which the transistor can be controlled. In particular, with multiple gates it is possible to use the SETs for current calibration. For this purpose, a defined, high-frequency voltage sequence is applied to the gates. In the first step, a gate creates contact to the source, while the conduction to the drain is suppressed by another gate. The setting is made so that exactly one electron can occupy the SET. In the next step, conduction to the source is suppressed and enabled to the drain. The electron is “pushed out” of the SET by voltage at another gate.

With the help of a circuit from SET, the measurement of the quantity of electrical current could potentially be traced back to the measurement of a frequency, as is already the case for the quantity of electrical voltage via the Josephson effect , and so a high-precision quantum standard could be based on a defined frequency of the electric current can be defined and represented.

A typical implementation option of the SET, for example, electronically contactable quantum dots that using photolithographic applied metal gates on modulation-doped GaAs - wafers . Another implementation option are very small metallic transitions with a thin insulating layer between the metallic contacts through which electrons can “ tunnel ”.

See also

literature

  • Leo P. Kouwenhoven , Charles M. Marcus et al .: Electron transport in quantum dots. In: Mesoscopic Electron Transport. NATO ASI Series E345, Kluwer, Dordrecht 1997, ISBN 0792347374 . ( available online)
  • Marc A. Kastner The single electron transistor and artificial atoms , Annalen der Physik, Volume 9, 2000, pp. 885-894, pdf
  • Hermann Grabert, Michel H. Devoret: Single Charge Tunneling: Coulomb Blockade Phenomena in Nanostructures . Kluwer Academic / Plenum Publishers, 1992, ISBN 0-306-44229-9 .

Web links

The single electron transistor (University of Koblenz) (PDF, 360 kB)

Individual evidence

  1. ^ TA Fulton, GJ Dolan: Observation of single-electron charging effects in small tunnel junctions . In: Physical Review Letters . tape 59 , 1987, pp. 109–112 , doi : 10.1103 / PhysRevLett.59.109 .
  2. DV Averin, KK Likharev: Coulomb Blockade of Tunneling, and Coherent Oscillations in Small Tunnel Junctions . In: J. Low Temperature Physics . tape 62 , 1986, pp. 345 (Moscow State University, Dept. of Physics preprint 23, 1985).