| 摘要 |
PURPOSE:To increase efficiency of photochemical reaction on the surface of a semiconductor by setting a band profile so that minority carrier generating by light inrradiation is transferred to and confined in a zone which forms energy barrier to majority carrier. CONSTITUTION:When light is irradiated to a semiconductor, in the zone III of the semiconductor, holes h<+> are formed in a valence band a and electrons e<-> in a conduction band b. The holes h<+> and electrons e<-> which participate in reaction are transferred to the zone II by energy gradient in the zone III. The electrons e<-> transferred to the zone II and confined there become excess, and the holes h<+> enter the zone II from the zone I . The holes h<+> entered the zone IIenter the zone III by diffusion before recombination, and is transferred to the zone IV by energy gradient, and participate in oxidation reaction on the surface of the semiconductor. Therefore, the quantum efficiency of the reaction exceeds 100%. |
