Optical functions of InGaP/GaAs epitaxial layers from 0.01 to 5.5 eV R. Ferrini, G. Guizzetti, M. Patrini, A. Parisini, L. Tarricone and B. Valenti Eur. Phys. J. B, 27 4 (2002) 449-458 Published online: 25 June 2002 DOI: 10.1140/epjb/e2002-00177-x