Abstract: Substrates are mounted on a plurality of susceptors respectively. The plurality of susceptors on which respective substrates are mounted are placed on a rotational mechanism so that the susceptors are vertically spaced at a predetermined interval. The rotational mechanism on which the plurality of susceptors are placed is rotated. The plurality of susceptors on which the substrates are mounted respectively are heated. Semiconductor thin-films are deposited by supplying a source gas to each of the susceptors that are heated while being rotated, the source gas having been heated while passing through gas flow paths of respective path lengths substantially equal to each other.

Abstract: A method for manufacturing a light emitting element is directed to a method for manufacturing a light emitting element of a III-V group compound semiconductor having a quantum well structure including In and N, including the steps of: forming a well layer including In and N; forming a barrier layer having a bandgap wider than a bandgap of the well layer; and supplying a gas including N and interrupting epitaxial growth after the step of forming the well layer and before the step of forming the barrier layer. In the step of interrupting epitaxial growth, the gas having decomposition efficiency higher than decomposition efficiency of decomposition from N2 and NH3 into active nitrogen at 900° C. is supplied. In addition, in the step of interrupting epitaxial growth, the gas different from a gas used as an N source of the well layer is supplied.

Abstract: Even if arsenic-containing wastewater includes an oxidizing substance, the arsenic can be reliably removed as a precipitate. A wastewater treatment method includes a preparation step (S10) of preparing wastewater containing an oxidizing substance and arsenic, a feeding step (S30), a precipitation step (S50), and a post-treatment step (S60). In the feeding step (S30), as much FeCl2 as necessary to reduce the oxidizing substances, such as polishing agents, is introduced into the wastewater. In the precipitation step (S50), to precipitate out the arsenic as a precipitate from the wastewater as at least a part of the precipitating flocculant, FeCl3 transformed from the FeCl2 by its reducing the oxidizing substance is utilized. In the post-treatment step (S60), the precipitate is removed from the wastewater.

Abstract: Provided are a method of growing a group III-V compound semiconductor, and method of manufacturing a light-emitting device and an electron device, in which risks are reduced and nitrogen can be efficiently supplied at low temperatures. The method of growing a group III-V compound semiconductor includes the following processes. First, gas containing at least one selected from the group consisting of monomethylamine and monoethylamine is prepared as a nitrogen raw material. Then, the group III-V compound semiconductor is grown using the gas by vapor phase growth.

Abstract: Even if arsenic-containing wastewater includes an oxidizing substance, the arsenic can be reliably removed as a precipitate. A wastewater treatment method includes a preparation step (S10) of preparing wastewater containing an oxidizing substance and arsenic, a feeding step (S30), a precipitation step (S50), and a post-treatment step (S60). In the feeding step (S30), as much FeCl2 as necessary to reduce the oxidizing substances, such as polishing agents, is introduced into the wastewater. In the precipitation step (S50), to precipitate out the arsenic as a precipitate from the wastewater as at least a part of the precipitating flocculant, FeCl3 transformed from the FeCl2 by its reducing the oxidizing substance is utilized. In the post-treatment step (S60), the precipitate is removed from the wastewater.