Investigation of the damage as induced by 1.7 MeV protons in an amorphous/crystalline silicon heterojunction solar cell

Current–voltage under illumination and quantum yield characteristics of an amorphous silicon/crystalline silicon hetero solar cell have been measured before and after exposure to high-energy (1.7 MeV) protons. A comparison of the measured wavelength-dependent quantum yield with calculated values enabled to determine the effective electron diffusion length of the crystalline silicon, that dropped from a value of 434 μm before to a value of 4 μm after irradiation with 5×1012 cm−2 protons. Good agreement has been obtained between measured and simulated data using DIFFIN,11Developed by the Electrical Engineering Department at the University of Rome “La Sapienza”. ite-element simulation program for a-Si:H/c-Si heterojunction solar cells, enabling us to extract the depth profile of the recombination rate and the density of states distribution in the semiconductor layers before and after irradiation.