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Highly organized and crystallized cubic and hexagonal mesoporous SnO2 thin films were selectively synthesized via an evaporation-induced self-assembly (EISA) process with SnCl4 as the precursor and a triblock copolymer (pluronic F127) as the template. The as-spin-coated films were treated in two separate aging steps. Initial aging in a relative humidity (RH) of 75−85% at 25 °C was essential for obtaining the transparent and highly organized mesoporous films. The introduction of 1-BuOH instead of EtOH in the Sn−sol solution induced the formation of a robust hexagonal mesophase. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and UV−visible spectroscopy revealed the mesopore structures of the SnO2 thin films to be periodically organized with uniform surfaces, highly crystallized in the cassiterite phase, and thermally stable up to 600 °C. The optical transparencies were greater than 97% in the visible-light range. The sheet resistances of the prepared cubic and hexagonal mesoporous SnO2 thin films were also analyzed.

WO 3 /TiO 2 was prepared by modifying the surface of TiO 2 with clusters of crystallized WO 3 . Previously, we have reported that the TiO 2 covered with the monolayer of WO 3 shows greatly enhanced photocatalytic activity under UV light in decomposing VOCs. Here we report that the WO 3 /TiO 2 can also be activated by visible light in the photocatalytic decomposition of gaseous 2-propanol. The structure of WO 3 /TiO 2 was examined by X-ray diffraction (XRD), TEM, UV-Visible and Raman spectra. The samples with 10 mol% of WO 3 annealed at 700 • C provide the optimum photocatalytic efficiency in visible range. We also suggest the mechanism for the WO 3 /TiO 2 working under visible light.

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2.5 nm-sized SnO 2 nanoparticles in rutile phase were loaded on the surface of 25 nm-sized TiO 2 (Degussa P-25) to form SnO 2 /TiO 2 nano-composite structure. Up to 10 mol%, the loaded SnO 2 nanoparticles were well-dispersed on the surface of TiO 2 without mutual agglomeration. The SnO 2 /TiO 2 with 1 mol% of SnO 2 demonstrated 1.5-1.7 times of photocatalytic activity compared to the pure TiO 2 in decomposing gaseous 2-propanol and in evolving CO 2 . The role of SnO 2 nanoparticles on TiO 2 surface is considered to be retardation of recombination rate between electrons and holes by trapping the photo-excited electrons from the conduction band of TiO 2 .

We present a study of the photoresist (PR) etching and the low-k materials damage using a ferrite-core inductively coupled plasma (ICP) etcher, in order to develop an etching process for the low-k dielectric devices. We reveal that the N2/O2 flow ratio and bias power affected the PR etching rate. By Fourier transform infrared spectroscopy and HF dipping test, we investigated the effect of the gas flow ratio and bias power on the amount of etching damage to the low-k material.