Large-grain polycrystalline silicon (poly-Si) films were prepared on foreign substrates by the epitaxial thickening of seed layers. The seed layers were formed by aluminum-induced crystallization (AIC). Large-grain n-i-p poly-Si solar cells were deposited on epitaxial seeds by hot-wire chemical vapor deposition (HWCVD). Highly (93%) crystalline fractions with a lateral grain size of 5 mu m and an intrinsic layer were grown without incubation. These techniques were employed to prepare large-grain poly-Si thin-film solar cells. An ITO/n-i-p (HWCVD)/p+ (AIC)/Ti/glass-structured poly-Si thin-film solar cell with an initial efficiency of 5.6% was obtained.