Practice question

**Semiconductor properties** distinguish from conductors and insulators by temperature dependence and doping response. At 0 K intrinsic acts as insulator, conductivity due to thermally generated electron-hole pairs, number of outer electrons 4 for Si/Ge forming covalent bonds, each atom shares electrons, crystal with N atoms has 4N valence electrons, 2N bonds. At T > 0 K , thermal energy excites electrons from the valence band to the conduction band, creating electron-hole pairs that contribute to conduction. Substituting values gives Electrons and holes, which matches expected behaviour for this semiconductor device configuration, confirming doping, depletion and rectifier principles.