Abstract: A method of producing a GaAs wafer having excellent OF orientation stability even in a GaAs wafer having an off angle, and a GaAs wafer group are provided. A method of producing a GaAs wafer includes: a grinding step of grinding a peripheral surface of a GaAs ingot including formation of a provisional orientation flat; a slicing step of slicing the GaAs ingot after the grinding step to cut out a material wafer having an off angle; and a cleaving step of applying marking to the material wafer according to an orientation of an orientation flat determined based on the provisional orientation flat and cleaving the material wafer toward a peripheral surface of the material wafer from the marking to form the orientation flat.

Abstract: To provide a flaky silver powder having a tapped density of from 0.8 g/mL to 1.9 g/mL, and a cumulative 50th percentile particle diameter (D50) of from 2 ?m to 7 ?m, where the cumulative 50th percentile particle diameter (D50) is measured by laser diffraction or laser scattering particle size analysis.

Abstract: Provided is a III-nitride semiconductor light-emitting device having excellent light output power as compared with conventional devices and a method of producing the same. The III-nitride semiconductor light-emitting device has an emission wavelength of 200 nm to 350 nm and includes an n-type semiconductor layer; a light emitting layer in which N barrier layers 40b and N well layers 40w (where N is an integer) are alternately stacked in this order; an AlN guide layer; an electron blocking layer; and a p-type semiconductor layer in this order. The electron block layer is made of p-type AlzGa1-zN (0.50?z?0.80), and the barrier layers are made of n-type AlbGa1-bN (z+0.01?b?0.95).

Abstract: Provided are a silver powder and a method of producing the same. The method of producing the silver powder includes a first surface smoothing step of causing fine silver particles having internal voids to mechanically collide with one another; a fine powder removal step of dispersing fine silver particles present after the first surface smoothing step using high-pressure airflow while removing fine powder; and a second surface smoothing step of causing fine silver particles present after the fine powder removal step to mechanically collide with one another.

Abstract: Provided are a silver powder having powder physical properties enabling reduction of volume resistivity after firing and a method of producing this silver powder. The silver powder has a tap density of 4.8 g/mL or more, a TAP/D50 value (value determined by dividing the tap density (g/mL) by the volume-based median diameter (?m)) of not less than 7 and not more than 15, and a specific surface area of not less than 0.75 m2/g and not more than 1.3 m2/g.

Abstract: A method of manufacturing a semiconductor optical device of this disclosure includes the steps of forming an etch stop layer on an InP growth substrate, the etch stop layer having a thickness of 100 nm or less; and forming a semiconductor laminate on the etch stop layer by stacking a plurality of InGaAsP-based III-V group compound semiconductor layers containing at least In and P. Further, an intermediate article of a semiconductor optical device of the present disclosure includes an InP growth substrate; an etch stop layer formed on the InP growth substrate, the etch stop layer having a thickness of 100 nm or less; and a semiconductor laminate formed on the etch stop layer, including a plurality of InGaAsP-based III-V group compound semiconductor layers containing at least In and P stacked one another.

Abstract: Provided is an Al-containing hexagonal ferrite magnetic powder which produces an excellent durability-improving effect on a magnetic recording medium, wherein uniform pulverization of the magnetic powder can be easily achieved by dispersion treatment in preparation of a magnetic coating material even in cases where the magnetic powder has a small primary particle size or has a composition which is likely to produce hard secondary particles. The magnetic powder for a magnetic recording medium is an Al-containing hexagonal ferrite magnetic powder having an Al/Fe molar ratio of 0.030 to 0.200, and has a particle size distribution in which the volume ratio of particles having a particle size of 30 ?m or more as measured by a laser diffraction particle size distribution analyzer with a dispersion pressure of 100 kPa is 5.0% or less, and an activation volume Vact of 1800 nm3 or less.

Abstract: Provided is a semiconductor light-emitting element having improved light emission output. The semiconductor light-emitting element includes a light-emitting layer having a layered structure in which a first III-V compound semiconductor layer and a second III-V compound semiconductor layer having different composition ratios are repeatedly stacked. The first and second III-V compound semiconductor layers each contain three or more types of elements that are selected from Al, Ga, and In and from As, Sb, and P. The composition wavelength difference between the composition wavelength of the first III-V compound semiconductor layer and the composition wavelength of the second III-V compound semiconductor layer is 50 nm or less. The ratio of the lattice constant difference between the lattice constant of the first III-V compound semiconductor layer and the lattice constant of the second III-V compound semiconductor layer is not less than 0.05% and not more than 0.60%.

Abstract: Provided is a semiconductor light-emitting device for which detrimental effects such as discoloration of an electrode or emission failure due to migration are suppressed even when a joint material containing Ag is used, and a method of producing the same. The semiconductor light-emitting device includes a p-type semiconductor layer, a p-type electrode provided on the p-type semiconductor layer, and a pad provided on the p-type electrode. The p-type electrode at least has an ohmic metal layer placed on the p-type semiconductor layer side and a barrier layer that is placed closer to the pad than the ohmic metal layer and includes a TiN layer. In a top view, when a region of the barrier layer that does not overlap an electrical connection region between the pad and the barrier layer is defined as a surface diffusion inhibiting surface, the surface diffusion inhibiting surface is formed in a circular pattern.

Abstract: A composite oxide powder including a composition formula (1), wherein the ratio ?/? of a surface area value ? (m2/g) calculated by a BET one-point method to a surface area value ? (m2/g) calculated from a formula (2) is greater than 1.0 and equal to or less than 1.5 and the surface area value ? is equal to or less than 20 m2/g. ABO3-? (1) (wherein A is one or more types of elements (La, Sr, Sm, Ca and Ba), B is one or more types of elements (Fe, Co, Ni and Mn) and 0??<1); and surface area value ? (m2/g)=specific surface area value ?-surface area value ?(2) (the specific surface area value ? (m2/g) is a value in a total pore size range measured by a mercury intrusion method. The specific surface area value ? (m2/g) is a value in a range of pore sizes that are larger than a 50% cumulative particle size.

Abstract: Provided is a GaAs wafer that can suitably be used to produce LiDAR sensors in particular and a method of producing a GaAs ingot that can be used to obtain such a GaAs wafer. The GaAs wafer has a silicon concentration of 5.0×1017 cm?3 or more and less than 3.5×1018 cm?3, an indium concentration of 3.0×1017 cm?3 or more and less than 3.0×1019 cm?3, and a boron concentration of 1.0×1018 cm?3 or more. The average dislocation density of the GaAs wafer is 1500/cm2 or less.

Abstract: A silver powder containing: silver particles; and an adherent that is attached to surfaces of the silver particles and contains a metal oxide that has a melting point lower than a melting point of silver.

Abstract: Provided is silver powder including silver particles having closed pores inside the particles, wherein when cross sections of the silver particles are observed at a magnification of 10,000, an average of numbers of the pores having Heywood diameters of 200 nm or greater relative to an area of the cross sections is 0.01 pores/?m2 or less, and wherein when the cross sections of the silver particles are observed at a magnification of 40,000, an average of numbers of the pores having Heywood diameters of 10 nm or greater but less than 30 nm relative to the area of the cross sections is 25 pores/?m2 or more.

Abstract: Provided are a III-nitride semiconductor light-emitting device that can reduce change in the light output power with time and has more excellent light output power, and a method of producing the same. A III-nitride semiconductor light-emitting device 100 has an emission wavelength of 200 nm to 350 nm, and includes an n-type layer 30, a light emitting layer 40, an electron blocking layer 60, and a p-type contact layer 70 in this order. The electron blocking layer 60 has a co-doped region layer 60c, the p-type contact layer 60 is made of p-type AlxGa1-xN (0?x?0.1), and the p-type contact layer 60 has a thickness of 300 nm or more.

Abstract: There is provided a bonding paste capable of forming a uniform bonding layer by reducing occurrence of voids at edges even when a bonding area is large, and bonding method using the paste, and provides a metal paste for bonding containing at least metal nanoparticles (A) having a number average primary particle size of 10 to 100 nm, wherein a cumulative weight loss value (L100) when a temperature is raised from 40° C. to 100° C. is 75 or less, and a cumulative weight loss value (L150) when a temperature is raised from 40° C. to 150° C. is 90 or more, and a cumulative weight loss value (L200) when a temperature is raised from 40° C. to 200° C. is 98 or more, based on 100 cumulative weight loss value (L700) when the paste is heated from 40° C. to 700° C. at a heating rate of 3° C./min in a nitrogen atmosphere.

Abstract: There are provided an inexpensive copper powder, which has a low content of oxygen even it has a small particle diameter and which has a high shrinkage starting temperature when it is heated, and a method for producing the same. While a molten metal of copper heated to a temperature, which is higher than the melting point of copper by 250 to 700° C. (preferably 350 to 650° C. and more preferably 450 to 600° C.), is allowed to drop, a high-pressure water is sprayed onto the heated molten metal of copper in a non-oxidizing atmosphere (such as an atmosphere of nitrogen, argon, hydrogen or carbon monoxide) to rapidly cool and solidify the heated molten metal of copper to produce a copper powder which has an average particle diameter of 1 to 10 ?m and a crystallite diameter Dx(200) of not less than 40 nm on (200) plane thereof, the content of oxygen in the copper powder being 0.7% by weight or less.

Abstract: Provided is a GaAs ingot with which a GaAs wafer having a carrier concentration of 5.5×1017 cm?3 or less and low dislocation density with an average dislocation density of 500/cm2 or less can be obtained by adding a small amount of In with Si. A seed side end and a center portion of a straight body part of the GaAs ingot each have a silicon concentration of 2.0×1017 cm?3 or more and less than 1.5×1018 cm?3, an indium concentration of 1.0×1017cm?3 or more and less than 6.5×1018 cm?3, a carrier concentration of 5.5×1017 cm?3 or less, and an average dislocation density of 500/cm2 or less.

Abstract: There are provided a spherical silver powder which has the same diameter as that of a spherical silver powder produced by a conventional wet reduction method and which can sufficiently sinter the silver particles thereof to cause the silver particles to be adhered to each other at a relatively low temperature to form a conductive film having a low volume resistivity when it is used for a baked type conductive paste, and a method for producing the same. A spherical silver powder, which contains a neutral or basic amino acid having a carbon number of not less than 5 in each of particles thereof and which has an average particle diameter D50 of 0.2 to 5 ?m based on a laser diffraction method, is produced by adding the neutral or basic amino acid having the carbon number of not less than 5 (such as proline, tyrosine, tryptophan, phenylalanine, arginine or histidine) to a water reaction system containing silver ions to mix a reducing agent therewith to deposit silver particles by reduction.

Abstract: A perovskite-type composite oxide powder is a perovskite-type composite oxide powder represented by a general formula ABO3-? (where ? represents an amount of deficiency of oxygen and 0??<1), an element contained in an A site is La, elements contained in a B site are Co and Ni and a crystallite size determined by a Williamson-Hall method is equal to or greater than 20 nm and equal to or less than 100 nm. In this way, when the perovskite-type composite oxide powder is used as an air electrode material for a fuel cell, an air electrode in which the resistance thereof is low and the conductivity thereof is high can be obtained.

Abstract: While a molten metal of copper heated to a temperature, which is higher than the melting point of copper by 250 to 700° C. (preferably 350 to 650° C. and more preferably 450 to 600° C.), is allowed to drop, a high-pressure water is sprayed onto the heated molten metal of copper in a non-oxidizing atmosphere (such as an atmosphere of nitrogen, argon, hydrogen or carbon monoxide) to rapidly cool and solidify the heated molten metal of copper to produce a copper powder which has an average particle diameter of 1 to 10 ?m and a crystallite diameter Dx(200) of not less than 40 nm on (200) plane thereof, the content of oxygen in the copper powder being 0.7% by weight or less.