Electrons migrate from the electron rich n-type material towards the p-type, while "holes" from the p-type migrate towards the n-type.  The result is an electric field also known as the Fermi-Dirac distribution.

Electrons migrate from the electron rich p-type material towards the n-type, while "holes" from the p-type migrate towards the n-type.  The result is an electric field also known as the Fermi-Dirac distribution

Electrons migrate from the electron rich n-type material towards the p-type, while "holes" from the p-type migrate towards the n-type.  The result is an electric field also known as the space-charge region.

Electrons migrate from the electron rich p-type material towards the n-type, while "holes" from the n-type migrate towards the p-type.  The result is an electric field also known as the space-charge region.