# Fermi energy and quasi-Fermi energies in pn-junctions

Hi,

Considering a pn-junction at thermal equilibrium, why does following count

EFp=EFn-eVd=EF,

where EFp and EFn are the quasi-Fermi energies in the neutral p- and n-type regions before equilibrium is established, with EFn>EFp, EF is the Fermi energy after equilibrium is established, and Vd is the diffusion potential? What I do not get, is how EFp can be equal to EF.