Abstract: A thermoelectric conversion material contains a matrix composed of a semiconductor and nanoparticles disposed in the matrix, and the nanoparticles have a lattice constant distribution ?d/d of 0.0055 or more.

Abstract: A thermoelectric conversion material includes: a base material that is a semiconductor composed of a base material element; a first additional element that is an element different from the base material element, has a vacant orbital in a d orbital or f orbital located internal to an outermost shell of the first additional element and forms a first additional level in a forbidden band of the base material; and a second additional element that is an element different from both of the base material element and the first additional element and forms a second additional level in the forbidden band of the base material. A difference is 1 between the number of electrons in an outermost shell of the second additional element and the number of electrons in at least one outermost shell of the base material element.

Abstract: A thermoelectric material element includes: a thermoelectric material portion composed of a thermoelectric material that includes a first crystal phase and a second crystal phase during an operation, the second crystal phase being different from the first crystal phase; a first electrode disposed in contact with the thermoelectric material portion; and a second electrode disposed in contact with the thermoelectric material portion and disposed to be separated from the first electrode. During the operation, the thermoelectric material portion includes a first temperature region having a first temperature, and a second temperature region having a second temperature lower than the first temperature of the first temperature region. A ratio of the first crystal phase to the second crystal phase in the first temperature region is larger than a ratio of the first crystal phase to the second crystal phase in the second temperature region.

Abstract: A thermoelectric conversion material includes: a base material that is a semiconductor; and an additive element that differs from an element constituting the base material. An additional band formed of the additive element is present within a forbidden band of the base material. A density of states of the additional band has a ratio of greater than or equal to 0.1 relative to a maximum value of a density of states of a valence band adjacent to the forbidden band of the base material.

Abstract: A plate-shaped thermoelectric conversion material having a first main surface and a second main surface on the opposite side of the first main surface is formed of semiconductor grains that are in contact with one another. The semiconductor grains each include a particle composed of a semiconductor containing an amorphous phase, and an oxidized layer covering the particle. The distance between the first main surface and the second main surface exceeds 0.5 mm.

Abstract: A thermoelectric conversion material contains a matrix composed of a semiconductor and nanoparticles disposed in the matrix, and the nanoparticles have a lattice constant distribution ?d/d of 0.0055 or more.

Abstract: A thermoelectric conversion material contains a matrix composed of a semiconductor and nanoparticles disposed in the matrix, and the nanoparticles have a lattice constant distribution ?d/d of 0.0055 or more.

Abstract: A semi-insulating gallium arsenide crystal substrate has a main surface with a plane orientation of (100) and a diameter of 2R mm, the main surface having a specific resistance with an average value of 5×107 ?·cm or more and with a standard deviation divided by the average value of the specific resistance, or with a coefficient of variation, of 0.50 or less in each of three measurement areas having their centers at distances of 0 mm, 0.5R mm, and (R-17) mm, respectively, from the center of the main surface in the [010] direction.

Abstract: A thermoelectric conversion material includes: a base material that is a semiconductor composed of a base material element; a first additional element that is an element different from the base material element, has a vacant orbital in a d orbital or f orbital located internal to an outermost shell of the first additional element and forms a first additional level in a forbidden band of the base material; and a second additional element that is an element different from both of the base material element and the first additional element and forms a second additional level in the forbidden band of the base material. A difference is 1 between the number of electrons in an outermost shell of the second additional element and the number of electrons in at least one outermost shell of the base material element.

Abstract: A thermoelectric material element includes: a thermoelectric material portion composed of a thermoelectric material that includes a first crystal phase and a second crystal phase during an operation, the second crystal phase being different from the first crystal phase; a first electrode disposed in contact with the thermoelectric material portion; and a second electrode disposed in contact with the thermoelectric material portion and disposed to be separated from the first electrode. During the operation, the thermoelectric material portion includes a first temperature region having a first temperature, and a second temperature region having a second temperature lower than the first temperature of the first temperature region. A ratio of the first crystal phase to the second crystal phase in the first temperature region is larger than a ratio of the first crystal phase to the second crystal phase in the second temperature region.

Abstract: A semi-insulating gallium arsenide crystal substrate has a main surface with a plane orientation of (100) and a diameter of 2R mm, the main surface having a specific resistance with an average value of 5×107 ?·cm or more and with a standard deviation divided by the average value of the specific resistance, or with a coefficient of variation, of 0.50 or less in each of three measurement areas having their centers at distances of 0 mm, 0.5R mm, and (R-17) mm, respectively, from the center of the main surface in the [010] direction.

Abstract: A gallium nitride substrate has a surface with a diameter of not less than 100 mm, a difference being not less than 0.1 cm?1 and not more than 2 cm?1 between maximum and minimum values of wave numbers at a maximum peak of peaks corresponding to an E2H phonon mode in micro-Raman scattering mapping measurement at each of square regions having sides each having a length of 2 mm, the square regions being located at a total of five locations including a central location and four circumferential edge locations on the surface of the gallium nitride substrate, a difference being not more than 2 cm?1 between maximum and minimum values of the wave numbers at the maximum peak of the peaks corresponding to the E2H phonon mode at all of measurement points in the five locations.

Abstract: A thermoelectric conversion material contains a matrix composed of a semiconductor and nanoparticles disposed in the matrix, and the nanoparticles have a lattice constant distribution ?d/d of 0.0055 or more.

Abstract: A plate-shaped thermoelectric conversion material having a first main surface and a second main surface on the opposite side of the first main surface is formed of semiconductor grains that are in contact with one another. The semiconductor grains each include a particle composed of a semiconductor containing an amorphous phase, and an oxidized layer covering the particle. The distance between the first main surface and the second main surface exceeds 0.5 mm.

Abstract: A gallium nitride substrate has a surface with a diameter of not less than 100 mm, a difference being not less than 0.1 cm?1 and not more than 2 cm?1 between maximum and minimum values of wave numbers at a maximum peak of peaks corresponding to an E2H phonon mode in micro-Raman scattering mapping measurement at each of square regions having sides each having a length of 2 mm, the square regions being located at a total of five locations including a central location and four circumferential edge locations on the surface of the gallium nitride substrate, a difference being not more than 2 cm?1 between maximum and minimum values of the wave numbers at the maximum peak of the peaks corresponding to the E2H phonon mode at all of measurement points in the five locations.

Abstract: A gallium nitride substrate has a surface with a diameter of not less than 100 mm, a difference being not less than 0.1 cm?1 and not more than 2 cm?1 between maximum and minimum values of wave numbers at a maximum peak of peaks corresponding to an E2H phonon mode in micro-Raman scattering mapping measurement at each of square regions having sides each having a length of 2 mm, the square regions being located at a total of five locations including a central location and four circumferential edge locations on the surface of the gallium nitride substrate, a difference being not more than 2 cm?1 between maximum and minimum values of the wave numbers at the maximum peak of the peaks corresponding to the E2H phonon mode at all of measurement points in the five locations.

Abstract: There is provided a gallium nitride substrate having a C plane as a surface with a diameter of not less than 100 mm, the gallium nitride substrate including first regions and second regions having different average values of band-edge emission intensities in a micro photoluminescence mapping at 25° C. in a square region located in the C plane and having sides each having a length of 2 mm, an average value Ibe1a of the band-edge emission intensities of the first regions and an average value Ibe2a of the band-edge emission intensities of the second regions satisfying the following relational expressions (I) and (II): Ibe1a>Ibe2a . . . (I) and 2.1?Ibe1a/Ibe2a?9.4 . . . (II).

Abstract: A thermoelectric conversion material includes: a base material that is a semiconductor; and an additive element that differs from an element constituting the base material. An additional band formed of the additive element is present within a forbidden band of the base material. A density of states of the additional band has a ratio of greater than or equal to 0.1 relative to a maximum value of a density of states of a valence band adjacent to the forbidden band of the base material.

Abstract: There is provided a gallium nitride substrate having a C plane as a surface with a diameter of not less than 100 mm, the gallium nitride substrate including first regions and second regions having different average values of band-edge emission intensities in a micro photoluminescence mapping at 25° C. in a square region located in the C plane and having sides each having a length of 2 mm, an average value Ibe1a of the band-edge emission intensities of the first regions and an average value Ibe2a of the band-edge emission intensities of the second regions satisfying the following relational expressions (I) and (II): Ibe1a>Ibe2a . . . (I) and 2.1?Ibe1a/Ibe2a?9.4 . . . (II).

Abstract: There is provided a gallium nitride substrate having a C plane as a surface with a diameter of not less than 100 mm, the gallium nitride substrate including first regions and second regions having different average values of band-edge emission intensities in a micro photoluminescence mapping at 25° C. in a square region located in the C plane and having sides each having a length of 2 mm, an average value Ibe1a of the band-edge emission intensities of the first regions and an average value Ibe2a of the band-edge emission intensities of the second regions satisfying the following relational expressions (I) and (II): Ibe1a>Ibe2a??(I) and 2.1?Ibe1a/Ibe2a?9.4??(II).