Effect of the Added Polyethylene Glycol Molecular Weight and Calcination Heating Rate on the Morphology of TiO₂ Films Formed by Sol-Gel

Abstract

This research investigated the changing morphology of silicon (Si)-supported titanium dioxide (TiO 2 ) thin lms with different heating rates and molecular weights (M W ) of the added polyethylene glycol (PEG). The TiO 2 lms were deposited on a Si wafer (100) by sol-gel spin coating with PEG (M W = 6,000 or 35,000 g·mol −1 ) as pore generating agents. Calcination at 450 C completely decomposed all the organic residues in the TiO 2 sol, and the resultant lms were in the anatase phase. The combustion nature of PEG was found to be the main factor controlling the lm s morphology, where the exothermic heat of PEG combustion tended to be higher with increased heating rates and dependent on the type of PEG (extended and folded chain crystal). At heating rates of 10 C·min −1 or higher, the exothermic heat led to localized grain coalescence in the TiO 2 lms, which decreased the lm porosity. However, this exothermic heat also simultaneously induced pore agglomeration. Hence, the average pore size of PEG-containing lms were larger than in lms without PEG. In contrast, the heating rate did not signicantly affect the morphology lms without PEG.

Effect of zirconium on physical properties and corrosion resistance of chromium and chromium nitride films

“…Coating were fabricated by many processes such as sol-gel spin coating, chemical vapor deposition (CVD) and physical vapor deposition (PVD) etc. [20,29,30]. Generally, selection of coating methods depends on coating materials, substrates and proposes of preparations.…”

“…Although film preparations could be done by several methods [25,29,30], magnetron sputtering is an outstanding method. It is convenience, powerful, reliable method and could perform in a wide range of temperature or work with reactive gases including nitrogen gas [20,31].…”