DOWA ELECTRONICS MATERIALS CO., LTD.

Provided is a method of producing a silver powder and the silver powder that enable preparation of a conductive paste capable of forming a wiring pattern with desired line width and height. A method of producing a silver powder comprises: a disintegration step of disintegrating an agglomerated silver powder in an airflow type mill 2 ; and a classification step of classifying a silver powder after the disintegration step, in a pneumatic classifier 3 , wherein the agglomerated silver powder has a moisture content of 2 wt % or more and 20 wt % or less, in the disintegration step, compressed air at a temperature of 80° C. or more and 180° C. or less is supplied to the airflow type mill 2 as supply air, in the classification step, an exhaust of the airflow type mill 2 and the silver powder after the disintegration step are supplied to the pneumatic classifier 3 , and the exhaust has a temperature of 30° C. or more and a volumetric humidity of 20 g/m 3 or more.

Provided is a reflective electrode for a deep ultraviolet light-emitting element that enables a balance of both high light emission output and excellent reliability. A method of producing the reflective electrode for a deep ultraviolet light-emitting element includes: a first step of forming Ni with a thickness of 3 nm to 20 nm as a first metal layer on a p-type contact layer having a superlattice structure; a second step of forming Rh with a thickness of not less than 20 nm and not more than 2 μm as a reflective metal on the first metal layer; and a third step of performing heat treatment of the first metal layer and the second metal layer at not lower than 300° C. and not higher than 600° C.

Provided are a silver powder that can reduce line resistance and a method of producing the same. The silver powder has a diameter at a cumulative value of 50% of 3 μm or more and a ratio of particles of 10 μm or larger of 10% or less. The silver powder includes flake-like particles having a major axis of 6 μm or more and irregularly shaped particles having a major axis of less than 6 μm, an average aspect ratio that is a ratio of average major axis relative to average thickness of the flake-like particles is 8 or more, and a shape factor that is a ratio of area of a circle having average maximum length of the irregularly shaped particles as a diameter relative to average particle area of the irregularly shaped particles is 1.7 to 1.9. Ignition loss is 0.1 wt % to 0.4 wt %.

Provided is an ultraviolet light receiving device having photosensitivity effective to target wavelengths in the ultraviolet region. A Schottky junction ultraviolet light receiving device has the photosensitivity peak wavelength in an ultraviolet region of 230 nm or more and 320 nm or less, and exhibits a rejection ratio of 10 5 or more, the rejection ratio being the ratio of the responsivity Rp to the peak photosensitivity wavelength to the average of the responsivity Rv to a visible region of 400 nm or more and 680 nm or less (Rp/Rv).

In a light-emitting element including a first InAs layer that is undoped or doped with an n-type dopant; an active layer including one or more InAs y Sb 1-y layers (0<y<1); and a second InAs layer doped with a p-type dopant, an Al x In 1-x As electron blocking layer (0.05≤x≤0.40) with a thickness of 5 nm to 40 nm is provided between the active layer and the second InAs layer.

A deep ultraviolet light-emitting element includes an n-type semiconductor layer, a light-emitting layer, a p-type electron blocking layer, and a p-type contact layer, in order, on a substrate. The p-type contact layer has a superlattice structure in which a first layer formed of Al x Ga 1-x N and a second layer formed of Al y Ga 1-y N are stacked alternately. The Al composition ratio y of the second layer is 0.15 or higher. The deep ultraviolet light-emitting element includes a reflective electrode consisting of Ni and Rh directly on an outermost second layer. A guide layer having an Al composition ratio larger than those of a barrier layer of the light-emitting layer and the p-type electron blocking layer is included between the p-type electron blocking layer and a well layer closest to the p-type electron blocking layer in the light-emitting layer. A volume ratio of Rh in the reflective electrode is 75% or higher.

There is provided a cuboid silver powder including silver particles having a BET specific surface area of 0.5 m 2 /g or less. An average aspect ratio of the cuboid silver powder is 1.2 or greater and less than 2.0 as determined by observing cross-sections of 100 or more silver particles from the silver particles. An average of a ratio represented by (Formula 1) below is 0.84 or greater. The ratio is a ratio of perimeter of one silver particle among the silver particles to perimeter of a rectangle circumscribing the one silver particle. L/(2×major axis+2×minor axis)   (Formula 1): where L is the perimeter (μm) of the one silver particle, and the major axis and minor axis are respectively a long side (μm) and short side (μm) of the rectangle of minimum area circumscribing an outline of cross-section of the one silver particle.

A perovskite-type composite oxide powder according to the present invention includes: La; and at least one type of element selected from the group consisting of Sr, Ca, Co, Ni, Mn and Fe, a BET specific surface area is less than 6.0 m 2 /g and a formula (1) below is satisfied: 1 ≤ { ( D 9 ⁢ 0 ⁢ B - D 1 ⁢ 0 ⁢ B ) / D 5 ⁢ 0 ⁢ B } / { ( D 9 ⁢ 0 ⁢ A - D 1 ⁢ 0 ⁢ A ) / D 5 ⁢ 0 ⁢ A } ≤ 2 . 1 ( 1 ) in the formula, D 10 is a cumulative 10% particle size by volume, D 50 is a cumulative 50% particle size by volume and D 90 is a cumulative 90% particle size by volume when a measurement was performed with a particle size distribution measuring device that uses a laser diffraction/scattering method, and a subscript “A” indicates a particle size after ultrasonic dispersion and a subscript “B” indicates a particle size before ultrasonic dispersion.

A hexagonal ferrite magnetic powder is significantly more useful for achieving simultaneously both the enhancement of the recording density and the enhancement of the SNR of a magnetic recording medium. The hexagonal ferrite magnetic powder contains Bi at a Bi/Fe molar ratio in a range of 0.035 or less, has a saturation magnetization σs of 42.0 Am 2 /kg or more and a Dx volume calculated based on the crystallite diameters of 1,800 nm 3 or less. A method for producing hexagonal ferrite magnetic powder includes a step of performing a treatment of immersing hexagonal ferrite magnetic powder containing Bi in a solution having dissolved therein a compound X that forms a complex with Bi, so as to elute a part of Bi existing in the hexagonal ferrite magnetic powder into the solution.

A method is provided for producing a silver powder which has a smaller particle size distribution than the conventional one without changing the type of surface treatment agent, and also for enabling a low resistance when the silver powder is made into a paste to form an electrode. The method for producing a silver powder includes adding an O/W-type emulsion containing micelles of a surface treatment agent having a volume-based cumulative 50% particle diameter D 50 obtained by a laser diffraction particle size distribution analysis of 1.5 μm or less to a slurry of a silver powder. The dispersibility of the silver powder in the slurry containing the silver powder is then improved.