Microstructure characterization of CIGS/GaP/Si tandem solar cells
Résumé
Conversion efficiencies of single-junction solar cells are very close to the theoretical Schockley-Queisser limit (~33%). Tandem solar cells can exceed this value combining a top cell optimized to absorb solar radiation in the UV/visible range with a bottom cell optimized for IR absorption. We have developed this type of cell using a Cu(In,Ga)S2 (CIGS) layer (band gap of 1.65-1.70 eV) deposited on a Si substrate (1.1 eV). Here, we combined different characterization techniques including S/TEM and TAP to try understanding the relation between microstructure and optoelectonic performances.