IMAGES OF GRAIN-BOUNDARIES IN POLYCRYSTALLINE SILICON SOLAR-CELLS BY ELECTRON AND ION-BEAM-INDUCED CHARGE COLLECTION

Selected grain boundaries in a polycrystalline solar cell have been im aged by the electron beam induced current (EBIC) technique of the scan ning electron micro-scope and the ion beam induced charge (IBIC) metho d, using a 2.0 MeV focused He+ ion beam. The IBIC maps show lower reso lution and weaker contrast in comparison to EBIC images, as a result o f the larger spot size of the ion beam. However, IBIC allows an analys is of the height of the charge pulses produced by single ions; example s of the spectra thus obtained at different regions of the cell are gi ven, and the relation between spectrum shape and local charge collecti on properties of the specimen is briefly discussed.