A p-i-n GaAs0.75P0.19N0.06 structure lattice-matched to Si was realized on a 2-in. Si (001) substrate for monolithic tandem solar cells. The sample structure had mirror-like surfaces without any indication of pinholes or microcracks. X-ray diffraction results showed that all the layers were coherently grown on the Si substrate. Transmission electron microscopy results evidently showed that a dislocation-free device structure was grown on the Si substrate. Finally, current-voltage characteristics showed rectifying properties with low reverse saturation current, which was indicative of the high crystallinity of the device layer. (C) 2017 The Japan Society of Applied Physics