Experimental verification of optically optimized CuGaSe2 top cell for improving chalcopyrite tandems M. Schmid, R. Caballero, R. Klenk, J. Krč, T. Rissom, M. Topič and M. Ch. Lux-Steiner EPJ Photovolt., 1 (2010) 10601 Published online: 11 October 2010 DOI: 10.1051/epjpv/2010002