Effect of the seed layer on surface morphology and humidity sensing property of CoTiO 3 nanocrystalline film

Abstract CoTiO 3 nanocrystalline film with enhanced humidity sensing property has been prepared via a two-step method. A nanostructured CoTiO 3 seed layer was firstly grown on silicate substrate by sol-gel process, and another CoTiO 3 layer was subsequently deposited on the seed layer by RF magnetron co-sputtering using TiO 2 and Co 2 O 3 targets. The influence of seed layer on the microstructure and humidity sensing property of the CoTiO 3 film was investigated, it was found that the seed layer facilitates the intrinsic growth of CoTiO 3 grain and improves the crystallinity. Meanwhile, the surface morphology changes from brick-like grain type to a pebble-like pattern. The uniformity and alignment of the grains are both strongly related to the underneath CoTiO 3 seed layer. The as-prepared CoTiO 3 multilayer displayed enhanced humidity sensing properties such as the sensitivity to 95%RH reached to 41.9. The response time and recovery time was dramatically shortened, from 50 s for the seed layer to 5 s for the multilayer.