n-ZnO:N/p-Si nanowire photodiode prepared by atomic layer deposition

Core-shell p-n junction diode was fabricated using the atomic layer deposition (ALD) of ZnO on p-Si nanowire (NW) array prepared by electroless etching method. I-V measurements have shown that the carrier concentrations in ALD ZnO for both of the core-shell and planar diodes are effectively controlled by nitrogen doping to a proper level to form rectifying junction. Responsivity of the core-shell device was about 0.98 A/W at 660 nm, which is significantly improved compared to planar device. The superior sensitivity of core-shell structure is attributed to the effective carrier separation and collection originating from the characteristic of core-shell NWs full depletion. (C) 2012 American Institute of Physics. [doi:10.1063/1.3679078]