This research has established the process to transplant GaAs solar cells from GaAs substrate to Si substrate without degrading the conversion efficiency. The conversion efficiency of GaAs solar cell bonded to Si substrate using epitaxial lift-off process is almost the same as that grown on GaAs substrate and is superior to that grown on Si substrate by heteroepitaxy. (C) 2004 Elsevier B.V. All rights reserved.