TiO 2 atomic layer deposition on ZrO 2 particles using alternating exposures of TiCl 4 and H 2O

Abstract

TiO 2 was deposited with atomic layer control on ZrO 2 particles using alternating exposures of TiCl 4 and H 2O. Transmission Fourier transform infrared (FTIR) spectroscopy was used to monitor the sequential surface chemistry in vacuum. The ZrO 2 particles initially displayed vibrational modes consistent with ZrOH * surface species. TiCl 4 exposure at 600 K removed the surface hydroxyls and subsequent H 2O exposure at 600 K produced TiOH * surface species. Repeating the TiCl 4 and H 2O exposures in an ABAB… reaction sequence deposited TiO 2 with atomic layer control. The intensity of the bulk vibrational modes for TiO 2 increased with the number of AB reaction cycles. The ZrO 2 particles after TiO 2 deposition were examined with transmission electron microscopy (TEM). The TEM images revealed ZrO 2 particles encapsulated by conformal TiO 2 films with a thickness of ∼16 Å after 40 AB reaction cycles. These TEM images are consistent with a TiO 2 atomic layer deposition (ALD) growth rate at 600 K of 0.4 Å/AB cycle.