Morphology-tunable assembly of periodically aligned Si nanowire and radial pn junction arrays for solar cell applications

► PASiNW arrays are fabricated via a templated catalytic chemical etching process. ► The diameter, length, packing density and the shape of SiNWs are precisely controlled. ► Current debate on formation mechanism of SiNW and the role of silver are clarified. ► Diameter and interspace of SiNW significantly affect the efficiency of solar cell. ► A high PCE of 4.1% is achieved for PASiNW radial pn junction-based solar cell.