In-Situ Characterization of the Proton Irradiation Induced Degradation of Thin Film Liquid Phase Crystallized Silicon on Glass Based Heterojunction Solar Cells with Interdigitated Back Contacts

:Heterojunction solar cells with thin film crystalline silicon absorber layer and amorphous silicon emitter have been prepared, using Liquid Phase Crystallized (LPC) Silicon on glass technology, combined with the use of interdigitated back contacts in order to minimize reflection and shadowing losses. The solar cells have been exposed to a proton beam of 68 MeV, that creates a homogeneous depth profile of defects in the solar cells. A first partial irradiation of the solar cell created a very high local defect concentration and after a strong initial decrease of the short circuit current, the degradation almost saturates. A subsequently homogeneous irradiation of the whole solar cell area – however – resulted in a continuous further degradation of the investigated solar cell. The inhomogeneous defect concentration of the solar cell after this 2-step degradation has been evidenced by LBIC imaging