Tin-catalyzed silicon nanowires (Sn-catalyzed SiNWs) are synthesized using the hydrogen radical-assisted deposition method and the prepared samples are examined for application of solar cells. Voluminous SiNWs with various growth directions are synthesized for 10min at 400°C through the vapor–liquid–solid and the vapor–solid mechanisms. Their diameters are approximately 20–120nm and their lengths extended to about 4μm. The formation mode of metal catalyst and growth models of SiNWs by this method are proposed. In the application of solar cells, a superior characteristic below 0.5% in reflectance are obtained. Furthermore, well-arranged large quantities of SiNWs are synthesized on a thinly Sn-coated (∼30nm) c-Si substrate.