David M King et al 2008 Nanotechnology 19 255604 doi:10.1088/0957-4484/19/25/255604
David M King1, Xinhua Liang1, Beau B Burton2, M Kamal Akhtar3 and Alan W Weimer1
Show affiliationsPigment-grade TiO2 particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO2 and Al2O3 layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO2 films were deposited using tris-dimethylaminosilane (TDMAS) and H2O2 at 500 °C. Trimethylaluminum and water were used as precursors for Al2O3 ALD at 177 °C. The photocatalytic activity of anatase pigment-grade TiO2 was decreased by 98% after the deposition of 2 nm SiO2 films. H2SO4 digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO2 digest rate was 40 times faster for uncoated TiO2 than SiO2 coated over a 24 h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H2O2 chemistry can deposit high quality, fully dense SiO2 films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO2 particles.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, etc.)
Issue 25 (25 June 2008)
Received 2 March 2008, in final form 7 April 2008
Published 15 May 2008
David M King et al 2008 Nanotechnology 19 255604
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