Solid State Devices

Hole: An empty state in the valence band is reffered to as hole. Electron Hole Pair(EHP): If the conduction band electron and the hole are created by the excitation of a valence band electron to the conduction band, they are called an electron-hole pair.

Naturally an individual atom has orbitals of different energy levels which can be represented by wave functions. When the atoms are brought together, their antibonding atoms diminisles and bonding orbitals form a band of energy.