Uniform deposition of ultra-thin TiO2 film on mica substrate by atmospheric pressure chemical vapor deposition: Effect of precursor concentration

The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl4 concentration on the initial deposition of TiO2 on mica by atmospheric pressure chemical vapor deposition (APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO2 grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl4 concentration increased from 0.38% to 2.44%. The grain size increased with the TiCl4 concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO2 clusters at the initial stage finally result to the agglomeration of fine TiO2 grains at high TiCl4 concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl4 concentration is below 0.90%.