Band gap

A band gap is the energy difference between two groups of electrons in a material, called the valence band and the conduction band. It determines whether a material behaves as an insulator, semiconductor, or conductor. When electrons gain enough energy to jump this gap, they can move freely and conduct electricity. In insulators, the gap is large, making it difficult for electrons to jump. In conductors, the gap is very small or nonexistent, so electrons can flow easily. Semiconductors have a moderate gap, allowing control over their electrical properties, which is essential for electronic devices.