Selective growth of ZnO nanorods and their applications to ferroelectric nanorods

Abstract

We describe the selective growth of ZnO nanorods by metalorganic chemical vapor deposition using Pt layers patterned on SiO2/Si by photolithography as nucleation sites, as well as their application to ferroelectric nanorods. The growth of ZnO nanorods on the SiO2 and Pt surfaces was quite different in the nucleation stage. Under specific growth conditions, no nucleation was observed on the SiO2 surface due to its stable and less reactive nature while nucleation easily occurred on Pt due to its catalytic properties. Using this difference, we achieved selective growth of c-axis oriented ZnO nanorods only on Pt dots with lateral dimensions of 40 μm × 40 μm and diameter of 300 nm on the SiO2/Si substrate. The average diameter and length of selectively grown ZnO nanorods were 70–80 nm and ∼10 μm, respectively. By depositing 100-nm-thick Pb(Zr,Ti)O3 layers on the selectively grown ZnO nanorods, Pb(Zr,Ti)O3-covered ZnO nanorods were successfully grown selectively on the patterned Pt layers. These results demonstrate the feasibility of position control of nanorod growth by self-assembly in combination with photolithography for future ferroelectric device applications.