A photocatalyst absorbs light and promotes a chemical reaction. Photocatalysis has received much attention in recent years because of its pollutant degrading properties, which offer important economic benefits. Although titanium dioxide is the most used photocatalyst, it is difficult to use indoors because illumination by ultraviolet rays produces its photocatalytic functions. One method of using it indoors is to use visiblelight-responsive photocatalysts. Cuprous oxide-decorated tungsten trioxide, a candidate material, has been studied extensively and has been identified as highly photocatalytic material under visible light. This paper presents a new method of decorating cuprous oxide using a solution plasma. Using the solution plasma process, cuprous oxide-decorated tungsten trioxide was synthesized in 10 min. Then it decomposed 85% of organic substances in 4 hr under visible light irradiation. This catalyst showed superior photocatalytic performance to that of commercial titanium dioxide under visible light irradiation of the same wavelength.
We have grown InAs quantum dots on InP and directly bonded InP/Si substrate using MOVPE where the strain of GaInAsP second cap layer were changed. We have investigated the density, size and optical characteristics dependent on difference of lattice mismatch of strain compensation layer.
