Ultrathin aligned ZnO nanorod arrays grown by a novel diffusive pulsed laser deposition method

ZnO nanorod (NR) arrays were grown on Si at elevated temperatures using a two-stage diffusive pulsed laser deposition (DPLD) technique. A thin (∼50 nm) seed-layer was first formed by pulsed laser ablation of ZnO in O2. The sample was then turned to face away from the propagation direction of the ablation plume, and the ablation process continued. A dense array of ultrathin NRs was seen to grow from the seed-layer. These NRs are thinner (d ∼ 10 nm), and display a ∼20-times higher aspect ratio than those grown by traditional PLD under otherwise identical process conditions.