Solution synthesis of Cu2O/Si radial nanowire array heterojunctions for broadband photodetectors

Cu2O/Si radial nanowire array heterojunctions were prepared by depositing Cu2O nanoparticles via surfactant-assisted chemical bath deposition on n-Si nanowire arrays that were fabricated by metal-assisted electroless etching. After 20 cycles of deposition, large numbers of Cu2O nanoparticles with diameters of around 70 nm form shells that wrap the upper segment of each Si nanowire. Using the rectifying effect of the Cu2O/Si pn junctions, high photodetection sensitivity under illumination at 405, 532 and 1064 nm is exhibited, with a maximal photoresponsivity of 13.05 mAW(-1) at 532 nm. The photocurrents are superior to those of Cu2O/Si planar heterojunctions.