Describe how current is produced in a semiconductor ❏ Discuss conduction electrons and holes ◆ Explain an electron-hole pair ◆ Discuss recombination ❏ Explain electron and hole current

Current in a Semiconductor: Current in a semiconductor is produced by the movement of free electrons and holes. Semiconductors are materials that have properties between conductors and insulators. They are not very good at conducting electricity like metals, but they can carry more current than insulators.

Conduction Electrons and Holes: In semiconductors, the current is carried by two types of charge carriers - conduction electrons and holes. Conduction electrons are the free electrons that are available for conduction. Holes, on the other hand, are the absence of an electron in an atom. When an electron moves from one atom to another, it leaves a hole behind. This hole acts as a positive charge carrier.

Electron-Hole Pair: An electron-hole pair is created when an electron in the valence band of a semiconductor absorbs energy and jumps to the conduction band, leaving a hole behind in the valence band. This process is called excitation. The electron in the conduction band and the hole in the valence band constitute an electron-hole pair.

Recombination: Recombination is the process where a conduction band electron loses energy and falls back into a hole in the valence band. This process annihilates both the electron and the hole, and the energy is usually released in the form of light or heat.

Electron and Hole Current: In a semiconductor, current is produced by the movement of both electrons and holes. The electron current is due to the movement of electrons from the negative terminal to the positive terminal. The hole current, on the other hand, is due to the movement of holes from the positive terminal to the negative terminal. The total current in the semiconductor is the sum of the electron and hole currents.