Semiconducteur for micro-electronics

I was asked to create a Word document about semiconductor microcomputers

The band of energies permitted in a solid is related to the discrete allowed energies “the energy levels of single, isolated atoms”. When the atoms are brought together to form a solid, these discrete energy levels become perturbed through quantum mechanical effects, and the many electrons in the collection of individual atoms occupy a band of levels in the solid called the valence band. Empty states in each single atom also broaden into a band of levels that is normally empty, called the conduction band. Just as electrons at one energy level in an individual atom may transfer to another empty energy level, so electrons in the solid may transfer from one energy level in a given band to another in the same band or in another band, often crossing an intervening gap of forbidden energies. Studies of such changes of energy in solids interacting with photons of light, energetic electrons, X-rays, and the like confirm the general validity of the band theory and provide detailed information about allowed and forbidden energies