Vertical aligned p-Si nanowires were fabricated by electroless wet chemical etching of Si wafer p-Si nanowires/ZnO thin film heterojunction diode was fabricated by depositing ZnO thin film on vertically aligned p-Si nanowire arrays Optical studies revealed that the Si nanowire surface has porous silicon like structure The junction properties were evaluated by measuring I-V and C-V characteristics I-V characteristics exhibited well defined rectifying behavior with a turn on voltage of 2 26 V and ideality factor of 45 (C) 2010 Elsevier Ltd All rights reserved