Boundary layer-assisted chemical bath deposition of well-aligned ZnO rods on Si by a one-step method

ZnO seed layers and well-aligned ZnO single-crystalline micro/nanorods were synthesized on bare Si in one step without the assistance of catalysts by chemical bath deposition. Scanning electron microscopy (SEM) images and X-ray diffraction patterns show that the alignment of ZnO rods on Si(100) could be adjusted by varying the substrates’ angles of incline, the reaction temperature, and the precursor concentration. Transmission electron microscopy cross-sectional images demonstrate that a polycrystalline seed layer with (0002) preferred orientation was formed between the well-aligned rods and Si substrate placed vertically while a randomly oriented layer was formed between the randomly aligned rods and Si substrate placed horizontally. The formation of seed layers and alignment of as-synthesized ZnO rods were attributed to the assistance of boundary layers in a chemical bath deposition system.