Takumi Ikenoue

Ultrasonic Spray-Assisted Solution-Based Vapor-Deposition of Aluminum Tris(8-hydroxyquinoline) Thin Films

Aluminum tris(8-hydroxyquinoline) (Alq3) thin films were fabricated by a vapor-deposition technique from its methanol solution, that is, by the ultrasonic-assisted mist deposition technique. The application of high ultrasonic power to the Alq3–methanol mixture resulted in a stable and transparent solution. Mist particles formed by ultrasonic atomization of the solution were used as the source for vapor-deposition at the substrate temperature of 100–200 °C. Optical absorption and photoluminescence characteristics indicated the formation of Alq3 thin films. The results promise the formation of thin films of a variety of organic materials by the solution-based technique.

Fabrication and characteristics of p-type Cu2O thin films by ultrasonic spray-assisted mist CVD method

P-type cuprous oxide (Cu2O) thin films were fabricated by an ultrasonic spray-assisted mist chemical vapor deposition (mist CVD) method. Copper(II) acetylacetonate was used as a precursor and deionized water was used as a solvent. Cu2O was grown at a temperature of 350 ?C and the films were gradually changed from Cu2O to CuO by increasing the growth temperature. The Cu2O film grown at 350 ?C showed p-type conductivity with a carrier concentration of 3.3 ? 1015 cm?3 and a Hall mobility of 0.2 cm2?V?1?s?1.

Mist Deposition Technique as a Green Chemical Route for Synthesizing Oxide and Organic Thin Films

Ultrasonic spray-assisted mist deposition techniques have been developed as a cost-effective and environmental friendly deposition method for oxide and organic thin films. The chemical vapor deposition (CVD) of a variety of oxide thin films having unique functions, such as Cr 2 O 3 , Cu 2 O, Fe 3 O 4 , and Al 2 O 3 thin films, has been demonstrated as well as high-quality ZnO and Ga 2 O 3 films ever reported. In addition to the films deposition by the CVD process, the deposition of organic material thin films from the source solution has also been achieved; as examples we have shown the patterned deposition of water-soluble fluorescent polymers with a metal mask. This may substitute the spin-coating technique and contribute to increase the source consumption efficiency in the thin film deposition. We appeal that the mist deposition is a unique and promising technique as a green chemical route for film deposition.