TiO₂ thin film deposition from solution using microwave heating

A new method has been devised for the deposition of TiO₂ thin films on conducting glass using a microwave reactor. The substrates are immersed in a diluted homogeneous aqueous solution which was prepared by mixing equal volumes of a fluorine-complexed titanium(IV) solution ([Ti] = 3.4×10^-2M) and 6.8×10^-2 M boric acid solution. Low microwave power and short deposition time have been used. The TiO₂ layers obtained are well-adhered, homogenous, with good specularity and colored by interference of reflected light. Their thickness is in the range of 100-500 nm. SEM experiments denote that films are formed by small crystallites having linear dimensions under 100 nm. Crystal dimensions depend on microwave power and deposition time. The layers show a high degree of crystallinity and the observed crystal phase is anatase. Microwave heating has proved to be an efficient and inexpensive method for solution growth of TiO₂ films; it should also be of importance for other materials layers grown from solution.