I have searched a lot on the internet for a simple explanation of these two terms. As I have understood these things (quantum physics), after reading from a lot of sources, is that in an atom there are discrete energy levels and electrons occupy the levels according to the least energy of the levels and no two electrons have the same quantum number i.e. electrons have different states in a particular energy level i.e. they have a unique quantum number, also the Fermi level is the highest energy occupied by electrons in a particular state at 0K. Now when many atoms come together the discrete energy levels form a band of energies such as the valence band. Now, in semiconductors we have the valence band, the conduction band and the forbidden band in the band diagram, so for an intrinsic semiconductor the Fermi level lies in the forbidden gap. How is this possible? What actually is Fermi Energy? What I understood about the Fermi-Dirac statistics is that it gives us the probability of finding an electron in a given band according to the no. of states present in the band and the no. of electrons etc. Am I correct? Can anyone please explain Fermi Energy and Fermi Level in layman terms? Thanks!!!