Analysis of the electron subsystem in 2D ferroelectric semiconductors is of considerable interest for the exclusive use of 2D systems in micro- and optoelectronics as well as for the close relation of this problem to investigations of some new effects. Some effects of two-dimensional spontaneous polarization on a ferroelectric p-n junction, which has sinusoidal type corrugation at interface, have theoretically been investigated. In order to calculate polarization, potential energy, etc. we have solved Poisson equation for this system. Due to the fact that the spontaneous polarization has a parallel component to the junction interface, an extra electrical potential energy arises. This potential energy is periodic due to the charge corrugation. Also, it is a,function of a dimensionless parameter related to polarization.