Abstract: The optical semiconductor of the present invention is an optical semiconductor containing In, Ga, Zn, O and N, and has a composition in which a part of oxygen (O) is substituted by nitrogen (N) in a general formula: In2xGa2(1-x)O3(ZnO)y, where x and y satisfy 0.2<x<1 and 0.5?y. In the general formula, x is preferably 0.5, and furthermore, y is preferably 1 or more and 6 or less, and more preferably 2 or 6. It is preferred that the optical semiconductor of the present invention have a wurtzite crystal structure. The optical semiconductor of the present invention is an excellent optical semiconductor because it has a smaller band gap, can utilize visible light, and has high carrier mobility and thus has high quantum efficiency.

Abstract: The method for producing the optical semiconductor of the present disclosure includes a mixing step of producing a mixture containing a reduction inhibitor and a niobium compound that contains at least oxygen in its composition; a nitriding step of nitriding the mixture by the reaction between the mixture and a nitrogen compound gas; and a washing step of isolating niobium oxynitride from the material obtained through the nitriding step by dissolving chemical species other than niobium oxynitride with a washing liquid. The optical semiconductor of the present disclosure substantially consists of niobium oxynitride having a crystal structure of baddeleyite and having a composition represented by the composition formula, NbON.

Abstract: A photoelectrochemical cell (100) includes: a semiconductor electrode (120) including a substrate (121), a first n-type semiconductor layer (122) disposed on the substrate (121), and a second n-type semiconductor layer (123) and a conductor (124) disposed apart from each other on the first n-type semiconductor layer (122); a counter electrode (130) connected electrically to the conductor (124); an electrolyte (140) in contact with surfaces of the second n-type semiconductor layer (123) and the counter electrode (130); and a container (110) accommodating the semiconductor electrode (120), the counter electrode (130) and the electrolyte (140).

Abstract: A reflex-reflecting sheeting of a type having on the surface of the sheeting many isolated small compartments which are respectively hermetically sealed in the form of cells is characterized in the structure in which a support film comprises an upper layer which is in contact with glass beads and a lower layer disposed on the opposite side and having larger cohesive force and rubbery elasticity than the upper layer, and a protective film made of a substantially unoriented resin. The sheeting thus constructed exhibits strong resistance against separation of the protective film and the support film even under high temperature and humidity.