A key issue for any application of polystyrene (PS) nanospheres as a structural template is to use deposition reactions that work at temperatures lower than the PS glass transition temperature (Tg ≈ 95 ºC). Reactions at higher temperatures than Tg will cause the PS to flow and disrupt the periodic structure. Hence, we first studied the thermal ALD deposition of TiO2 from TDMAT and water at 85 ºC. Figure shows a cross sectional SEM micrograph of TiO2 deposited on Si from 600 cycles of TDMAT and water at 150 ºC. This is a conventional temperature for TDMAT-based TiO2 ALD, but significantly higher than Tg. This deposition produced a TiO2 layer of roughly 32 nm thickness, or a growth rate of 0.5 Å cycle -1 .