Principle
Performing this experiment is not difficult and it can be
carried out in daylight as any light interference is shielded by
the tube.
Benefits
- Specified for the requirements of the german final secondary-school examinations
- Especially for secondary schools
- Quantum and wave optics in a student experiment
Tasks
When is an LED a receiver? A light emitting diode or LED is an
electronic semiconductor component. If a current flows through the
LED in the conduction direction it emits light. Physically,
semiconductors are characterised by a band gap, i.e. an
energetically forbidden zone for electrons. This energy gap between
the valence band and the conducting band essentially determines the
electrical and optical properties. E.g. a photon whose energy is
less than the band gap energy of the semiconductor cannot create an
electron-hole pair. In this experiment you will determine the size
of the band gaps of the LED relative to one other.