Seed-layer induced growth of high-quality oriented ZnO films by a sol–gel process

A two-step process was developed to grow high-quality oriented ZnO films on Si (1 0 0) substrates, which included the pre-deposition of a very thin ZnO film (seed layer) by pulsed laser deposition and the subsequent sol-gel spin-coating of ZnO films. The effects of the seed layer on the orientation, crystallinity, and morphology of ZnO films were investigated. Results show that ZnO films on the seed layer exhibit a single (0 0 2) orientation, but that on the bare silicon substrate is multi-oriented. Compared with ZnO films on the bare silicon substrate, the crystallinity of ZnO films on the seed layer is enhanced obviously at high preheating temperatures above 500 °C. In addition, ZnO films on the seed layer have a denser internal structure than that on Si (1 0 0). These results indicate the seed layer may effectively induce the growth of high-quality oriented ZnO films by sol–gel.