2DEG

A two-dimensional electron gas (2DEG ) is a semiconductor structure in which electrons can move only in two dimensions effectively. In 2DEG many effects occur that do not occur in three-dimensional systems, such as the quantum Hall effect.

The movement of electrons can also be limited to even fewer dimensions. One limitation to one dimension results in quantum wires. One limitation to zero dimensions is called quantum dot, sometimes designer atom.

Generation

2DEG may be formed by two semiconductor layers of different band gap, and with significantly different Fermi level to be applied to one another. To compensate for this difference in the Fermi energy of the boundary layer flow to some of the electrons to the other semiconductor, thereby producing a local electric field. This can give a relatively sharply defined on the boundary layer energy minimum in the conduction band. Electrons that are in this minimum, do not have enough energy to leave the same.

As this energy minimum is perpendicular to the boundary layer very closely, follows from quantum mechanics that the motion is quantized in this direction with a relatively large energy gap between the ground state and the first excited state. However, the movement is parallel to the plane virtually not restricted. As long as the kinetic energy of the excitation energy below the first excited state is perpendicular to the boundary layer, the electron is therefore limited to only two degrees of freedom.

See also

2D ADGAS

  • Quantum mechanics
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