Abstract: A nitride semiconductor light-emitting element includes an active layer comprising at least one well layer, a p-type semiconductor layer located on one side of the active layer, and an electron blocking stack body located between the active layer and the p-type semiconductor layer. The electron blocking stack body includes a first electron blocking layer and a second electron blocking layer that is located on the p-type semiconductor layer side relative to the first electron blocking layer and has a lower Al composition ratio than that of the first electron blocking layer. When a total number of the well layers in the active layer is N, a film thickness of the first electron blocking layer is a film thickness d [nm] and an Al composition ratio of the second electron blocking layer is an Al composition ratio x [%], relationships 0.1N+0.9?d?0.2N+2.0 and 10N+40?x?10N+60 are satisfied.

Abstract: A nitride semiconductor light-emitting element includes a substrate including a growth surface that is a c-plane having an off angle, an AlN buffer layer comprising AlN and being formed on the growth surface, an n-type semiconductor layer formed on the AlN buffer layer, an active layer being formed on the n-type semiconductor layer and emitting ultraviolet light, and a p-type semiconductor layer formed on the active layer. An upper surface of the AlN buffer layer includes a step-and-terrace structure including a plurality of terraces and a plurality of steps connecting between the terraces. An average of heights of the plurality of steps is not more than 7.1 nm. An average of widths of the plurality of terraces is not more than 350 nm.

Abstract: A nitride semiconductor light-emitting element includes an n-type semiconductor layer, a p-type semiconductor layer, an active layer provided between the n-type semiconductor layer and the p-type semiconductor layer, and an electron blocking layer comprising Al and being provided between the active layer and the p-type semiconductor layer. The electron blocking layer partially includes a high Al composition portion in at least one cross section orthogonal to a stacking direction, the high Al composition portion having an Al composition ratio higher than a surrounding portion.

Abstract: A nitride semiconductor light-emitting element includes a substrate having a c-plane as a growth surface, a buffer layer formed on the growth surface, an n-type semiconductor layer formed on the buffer layer, an active layer being formed on the n-type semiconductor layer and emitting ultraviolet light at a central wavelength of not more than 365 nm, and a p-type semiconductor layer formed on the active layer. A film thickness of the buffer layer is more than 500 nm. An average oxygen concentration in the buffer layer satisfies not more than 4.5×1021 atoms/cm3.

Abstract: A nitride semiconductor light-emitting element includes an n-type semiconductor layer, an active layer being formed on the n-type semiconductor layer and emitting ultraviolet light, an electron blocking layer formed on the active layer, and a p-type semiconductor layer formed on the electron blocking layer. A plurality of pits are formed at least in the active layer. A ratio R=D2/D1, which is a ratio of a second density D2 to a first density D1, is less than 30%, where the first density D1 is a density of the pits on an upper surface of the active layer and the second density D2 is a density of the pits on an upper surface of the electron blocking layer.

Abstract: A light output prediction method for nitride semiconductor light-emitting element that is a method for predicting light output of a nitride semiconductor light-emitting element, the method including a model creation step of creating a trained model by learning at least a correlation of at least one of a composition parameter or a physical property parameter of a layer constituting the nitride semiconductor light-emitting element and a manufacturing condition parameter, relative to light output of the nitride semiconductor light-emitting element; and a light output prediction step of predicting light output using the trained model. In the model creation step, at least one of the composition parameter or the physical property parameter of a predetermined layer of the nitride semiconductor light-emitting element is used for the learning, and a growth temperature of the predetermined layer is used as the manufacturing condition parameter for the learning.

Abstract: A lifetime prediction method for nitride semiconductor light-emitting element that is a method for predicting lifetime of a nitride semiconductor light-emitting element, the method including a model creation step of creating a trained model by learning at least a correlation of at least one of a composition parameter or a physical property parameter of a layer constituting the nitride semiconductor light-emitting element and a manufacturing condition parameter, relative to lifetime of the nitride semiconductor light-emitting element; and a lifetime prediction step of predicting lifetime using the trained model. In the model creation step, at least one of the composition parameter or the physical property parameter of a predetermined layer of the nitride semiconductor light-emitting element is used for the learning, and a growth temperature of the predetermined layer is used as the manufacturing condition parameter for the learning.

Abstract: A nitride semiconductor light-emitting element includes an n-type semiconductor layer, an active layer that is formed on one side of the n-type semiconductor layer and includes a well layer and a barrier layer, an electron blocking layer that is formed on the active layer on an opposite side to the n-type semiconductor layer, and a p-type semiconductor layer formed on the electron blocking layer on an opposite side to the active layer. The electron blocking layer includes a plurality of semiconductor layers that are undoped. Among the plurality of semiconductor layers constituting the electron blocking layer, a first electron blocking layer located closest to the active layer has a higher Al composition ratio than that of the other semiconductor layers constituting the electron blocking layer and that of the barrier layer. A film thickness of the first electron blocking layer is less than 2 nm.

Abstract: A nitride semiconductor light-emitting element includes an n-type semiconductor layer, a p-type semiconductor layer, an active layer, and an electron blocking layer comprising at least one layer. The at least one layer of the electron blocking layer includes a peak-containing layer having an n-type impurity concentration peak in an n-type impurity concentration distribution along a stacking direction. The n-type impurity concentration peak appears as a local maximum in the n-type impurity concentration distribution along the stacking direction in the peak-containing layer and has an n-type impurity concentration of not less than 10 times a smallest value of the n-type impurity concentration in a region along the stacking direction between positions that are separated from a position of the peak in the stacking direction on both sides in the stacking direction by 10% of a thickness of the peak-containing layer.

Abstract: Manufacturing a nitride semiconductor light-emitting device includes a depositing an n-type cladding layer and an active layer with a multi-quantum well structure having a plurality of well layers on a substrate in a chamber. In depositing the active layer, a silicon source is not supplied into the chamber. The method includes supplying the silicon source into the chamber after depositing the n-type cladding layer and before depositing the active layer thereby, when a well layer located second from the n-type cladding layer side among the plurality of well layers is defined as a second well layer, a peak of distribution of a silicon concentration in a stacking direction of the n-type cladding layer and the active layer appears in a range where the second well layer is formed, and the silicon concentration at an apex of the peak is not less than 1.49×1018 atoms/cm3 and not more than 4.96×1018 atoms/cm3.

Abstract: A nitride semiconductor light-emitting element outputs ultraviolet light. The nitride semiconductor light-emitting element includes an active layer including a quantum well structure that generates the ultraviolet light, a dislocation suppression structure-containing layer being formed on the active layer and including a dislocation suppression structure that stops or bends a dislocation from the active layer; and a p-type contact layer being formed on the dislocation suppression structure-containing layer and having a thickness of not less than 10 nm and not more than 30 nm.

Abstract: A nitride semiconductor light-emitting element includes a light-emitting layer comprising a well layer comprising AlGaN and emitting ultraviolet light; an electron blocking layer being located on the light-emitting layer and comprising AlGaN with a first Al composition ratio higher than an Al composition ratio of the well layer; and a p-type cladding layer being located on the electron blocking layer, comprising AlGaN with a second Al composition ratio higher than the Al composition ratio of the well layer and lower than the first Al composition ratio, and being doped with a predetermined concentration of a p-type dopant. An interface between the electron blocking layer and the p-type cladding layer is doped with not less than a predetermined amount of an n-type dopant.

Abstract: A gas sensor 1 according to the present invention includes: a gas sensor element 22; a box-like casing 3 having a wall portion 3B1 provided with a gas introduction port 3B2; a circuit board 4 having a mounting surface 4a on which the gas sensor element 22 is mounted, and disposed inside the casing 3 such that the mounting surface 4a is away from the wall portion 3B1 and the gas sensor element 22 overlaps with the gas introduction port 3B2; and an annular elastic seal body 5 formed on the mounting surface 4a so as to surround the gas sensor element 22, and disposed between the mounting surface 4a and the wall portion 3B1. The elastic seal body 5 is made of sulfur-free condensation silicone resin.

Abstract: A nitride semiconductor light-emitting element emits ultraviolet light at a central wavelength of more than 320 nm and not more than 365 nm. The nitride semiconductor light-emitting element includes a substrate having a c-plane as a growth surface and a nitride semiconductor layer stacked on the growth surface of the substrate. The nitride semiconductor layer includes an n-type semiconductor layer, and an active layer being formed on the n-type semiconductor layer on the opposite side to the substrate and comprising a single quantum well structure with one well layer. The n-type semiconductor layer has an Al composition ratio of not more than 50% and a film thickness of more than 2 ?m. A composition difference obtained by subtracting an Al composition ratio of the well layer from the Al composition ratio of the n-type semiconductor layer is not less than 22%.

Abstract: A nitride semiconductor light-emitting element includes a light-emitting layer comprising a well layer comprising AlGaN and emitting ultraviolet light; an electron blocking layer being located on the light-emitting layer and comprising AlGaN with a first Al composition ratio higher than an Al composition ratio of the well layer; and a p-type cladding layer being located on the electron blocking layer, comprising AlGaN with a second Al composition ratio higher than the Al composition ratio of the well layer and lower than the first Al composition ratio, and being doped with a predetermined concentration of a p-type dopant. An interface between the electron blocking layer and the p-type cladding layer is doped with not less than a predetermined amount of an n-type dopant.

Abstract: A method for manufacturing a nitride semiconductor light-emitting element includes growing a p-type cladding layer with an average Al composition ratio in a thickness direction of not less than 70%, and growing a p-type contact layer with an Al composition ratio of not more than 10%. A flow rate ratio Fp/FIII is a p/III ratio and a flow rate ratio FV/FIII is a V/III ratio. The p-type cladding layer is grown in the growing the p-type cladding layer at a growth rate of not more than 2.5 nm/min, a p/III ratio of not less than 0.0002 and not more than 0.0400 and a VIII ratio of not more than 7000. The p-type contact layer is grown in the growing the p-type contact layer at a growth rate of not more than 3.3 nm/min, a p/III ratio of not less than 0.0200 and a V/III ratio of not less than 10000.

Abstract: A nitride semiconductor light-emitting element includes an n-type semiconductor layer; a p-type semiconductor layer; an active layer provided between the n-type semiconductor layer and the p-type semiconductor layer; and an electron blocking layer provided between the active layer and the p-type semiconductor layer. A film thickness of the electron blocking layer is not more than 100 nm. An average value of a hydrogen concentration over the electron blocking layer in a stacking direction of the n-type semiconductor layer, the active layer, the electron blocking layer and the p-type semiconductor layer is not more than 2.0×1018 atoms/cm3. A boundary portion between the p-type semiconductor layer and the electron blocking layer includes an n-type impurity.

Abstract: A nitride semiconductor light-emitting element includes an n-type semiconductor layer; a p-type semiconductor layer; an active layer provided between the n-type semiconductor layer and the p-type semiconductor layer; and an electron blocking layer provided between the active layer and the p-type semiconductor layer. At least one of the p-type semiconductor layer and the electron blocking layer includes an oxygen-containing portion including oxygen. An oxygen concentration at each position of the oxygen-containing portion in a stacking direction of the n-type semiconductor layer, the active layer, the electron blocking layer and the p-type semiconductor layer is not less than 2.5×1016 atoms/cm3.

Abstract: A nitride semiconductor light-emitting element includes an n-type cladding layer including n-type AlGaN, and a multiple quantum well layer including a barrier layer that includes AlGaN and is located on the n-type cladding layer side, wherein the nitride semiconductor light-emitting element further comprises a trigger layer that is located between the n-type cladding layer and the barrier layer and comprises Si, wherein a plural V-pits starting from dislocations in the n-type cladding layer and ending in the multiple quantum well are formed in the n-type cladding layer and the multiple quantum well layer.

Abstract: A nitride semiconductor light-emitting element includes an active layer comprising at least one well layer, a p-type semiconductor layer located on one side of the active layer, and an electron blocking stack body located between the active layer and the p-type semiconductor layer. The electron blocking stack body includes a first electron blocking layer and a second electron blocking layer that is located on the p-type semiconductor layer side relative to the first electron blocking layer and has a lower Al composition ratio than that of the first electron blocking layer. When a total number of the well layers in the active layer is N, a film thickness of the first electron blocking layer is a film thickness d [nm] and an Al composition ratio of the second electron blocking layer is an Al composition ratio x [%], relationships 0.1N+0.9?d?0.2N+2.0 and 10N+40?x?10N+60 are satisfied.