(c) Dr Paul Kinsler. [Acknowledgements & Feedback]

This is part of an information maze -- see the index-file for the full picture.

Excitons

These are objects that only occur in particular sorts of materials, such as semiconductors. An exciton is made up of an electron and a "hole" These have opposite electric-charge and attract each other -- they can be thought of as orbiting each other. Because of their mutual attraction, an exciton is more (energetically) favourable than being free for the electron and hole to be in.

Because the exciton is an electron orbiting a lack of an electron, it is possible for the electron to jump into the hole, causing the exciton to vanish. Because this "recombination" releases energy, this process usually emits light.

However, the right conditions for both free electrons and holes to exist at the same time do not occur in all cases, but we can easily make or find situations where they do.

Excitons can interact with light to form exciton polaritons.

XINDEX: semiconductor, quantum-wire, quantum-well, quantum-dot, polariton, phonon, index-file.

19971128 14 12 19961107 (c) Paul Kinsler

XKEYWORD: exciton

Email Feedback: Dr.Paul.Kinsler@physics.org

LOGBUG