Nuclear Method of Measurement of Diffusion Length in P-N Junctions

A P-N Germanium junction has been irradiated with 4,8 MeV, 6 MeV, 8,7 MeV alpha particles and 5 MeV , 10 MeV and 11 MeV protons ; the incident particles penetrate into the crystal perpendicularly to the Junction plane. The depletion region is 0,7 micron wide and is located at a distance of 5,3 ¿ from the crystal surface. The variation of the charge collection efficiency vs incident particle range in the material gives an accurate mean of calculating the diffusion length of the minority carriers in the base material.