THE POROUS SILICON EMITTER CONCEPT APPLIED TO MULTICRYSTALLINE SILICON SOLAR-CELLS

We report on the application of porous silicon (PS) as an antireflecti on coating material for commercial multicrystalline silicon solar cell s. A PS layer was formed on the thin emitter of n(+)/p junctions (0.3 mu m thick) produced for optimal photovoltaic characteristics with the front contact grid already deposited. This technique allows us to res trict PS formation to the areas between the grid fingers without chang ing the front contact (selective PS formation). Reflectivity measureme nts, quantum efficiencies and I-V characteristics are presented and ca refully compared with the performances of cells using a classical anti reflection coating (SiO2 + TiO2) in order to evaluate the effectivenes s of PS. The photovoltaic characteristics of the PS n(+)/p junctions a re comparable to those of the best multicrystalline solar cells produc ed commercially by the same manufacturer of the n(+)/p junction. (C) 1 997 Elsevier Science S.A.