Electrical and Electronic Engineer || learn about Semiconductor || VLSI enthusiast
Is there any band other than valence band and conduction band of any atom and if any how much external force is required to remove that band? Answer: The electronic band structure of an atom generally consists of two main bands: 1. Valence Band: Where electrons reside and are in a barrier state at certain energy levels. 2. Conduction Band: Where electrons can move and generate electric current. There is an energy gap between these two bands, which is called Band Gap. Generally, in semiconductors and insulators electrons have to cross this band gap from the valence band to the conduction band. Beyond this there is another level, which is called (Core Band or Deeper Level). It is very low and the electrons in it are bound very deeply, so they are not usually active in chemical or electronic processes. Removing an electron from the core band requires a lot of energy, which is usually much larger than the band gap. To extract core electrons: - requires external energy which is usually possible with high-energy photons such as X-rays or gamma rays. - The energy for this can be of the order of keV or MeV, which is much higher than the electron lifting from the valence band to the conduction band. Thus, core levels lie outside the valence and conduction bands, and high energy beams are required to extract core electrons
