What type of electrons do semiconductors generally have in their valence shell?

Semiconductors are materials that have four electrons in their valence shell. This characteristic is significant because it allows semiconductors to form covalent bonds with other atoms. When semiconductors are doped with impurities, either n-type (with additional electrons) or p-type (with holes), they can significantly alter their electrical conductivity. The four valence electrons of semiconductor materials, such as silicon or germanium, are essential for their ability to effectively conduct electricity under certain conditions, making them crucial for various electronic applications. This ability to manipulate conductivity by introducing impurities is what allows semiconductors to function in devices like diodes and transistors.