key term - Electron conduction

Definition

Electron conduction is the process by which electrons move through a material, allowing it to conduct electricity. This phenomenon is closely tied to the structure of solids, particularly how electrons fill energy bands in the material. In conductive materials, such as metals, the arrangement of atoms and available energy levels facilitate the flow of electrons, which contributes to their electrical properties.

5 Must Know Facts For Your Next Test

1. In metals, electron conduction occurs easily due to the presence of partially filled conduction bands, which allow electrons to flow freely.
2. Insulators have a full valence band and a wide band gap to the conduction band, making electron conduction very limited or non-existent.
3. Semiconductors can conduct electricity under certain conditions, as they have a smaller band gap that allows some electrons to jump from the valence band to the conduction band.
4. Temperature affects electron conduction: increasing temperature typically provides electrons with enough energy to jump into the conduction band, enhancing conductivity.
5. Doping semiconductors with specific impurities can significantly increase their conductivity by introducing additional energy levels within the band gap.

Review Questions

• How does the arrangement of energy bands in metals facilitate electron conduction?
  • In metals, the energy bands consist of a conduction band that is partially filled with electrons. This allows for easy movement of electrons when an electric field is applied. The presence of overlapping energy bands means that there are available states for electrons to move into without needing to gain much energy, which leads to high conductivity.
• Compare and contrast electron conduction in conductors and insulators based on their band structure.
  • Conductors have overlapping conduction and valence bands, allowing electrons to move freely and conduct electricity effectively. In contrast, insulators have a fully occupied valence band and a wide band gap to the conduction band, preventing electrons from jumping and thus limiting electron conduction. This fundamental difference in their band structures leads to distinct electrical properties.
• Evaluate the role of temperature and doping on the electron conduction properties of semiconductors.
  • Temperature plays a crucial role in electron conduction in semiconductors. As temperature increases, more electrons gain enough energy to transition from the valence band to the conduction band, enhancing conductivity. Doping introduces impurity atoms that add extra energy levels within the band gap, allowing more charge carriers to contribute to conduction. Together, these factors significantly improve the electrical performance of semiconductors in various applications.

Related terms

Conduction Band: The range of energy levels in a solid where electrons are free to move and contribute to electrical conduction.

Valence Band: The range of energy levels in a solid where electrons are bound to atoms and not free to move; it is filled with electrons in insulating materials.

Semiconductor: A material with electrical conductivity between that of a conductor and an insulator, whose conduction properties can be altered by temperature or impurities.