A device includes a semiconductor substrate containing gallium nitride and having a crystal face inclined from 0.05 to 15 inclusive with respect to the c-plane. The semiconductor substrate includes an irregular portion on the crystal face, and the contact angle of pure water having a specific resistance of 18 M.Math.cm or more on the surface of the irregular portion is 10 or less.

A device includes a semiconductor substrate containing gallium nitride and having a crystal face inclined from 0.05 to 15 inclusive with respect to the c-plane. The semiconductor substrate includes an irregular portion on the crystal face, and the contact angle of pure water having a specific resistance of 18 M.Math.cm or more on the surface of the irregular portion is 10 or less.

Provided is a cladded single crystal sapphire optical device (e.g., a s sapphire optical fiber or wafer). In one embodiment, the innovation provides a method for forming a cladding in a single crystal sapphire optical device by reactor irradiation. The reactor irradiation creates ions external to the optical device that enter the optical device, displace atoms in the optical device, and are implanted in the optical device, thus modifying the index of refraction of the optical device near the surface of the optical device and creating a cladding in the sapphire optical device.

Provided is a cladded single crystal sapphire optical device (e.g., a s sapphire optical fiber or wafer). In one embodiment, the innovation provides a method for forming a cladding in a single crystal sapphire optical device by reactor irradiation. The reactor irradiation creates ions external to the optical device that enter the optical device, displace atoms in the optical device, and are implanted in the optical device, thus modifying the index of refraction of the optical device near the surface of the optical device and creating a cladding in the sapphire optical device.

A method includes mixing first and second alloys to form a mixture, pressing the mixture within a first magnetic field to form a magnet having anisotropic particles of the first alloy aligned with a magnetic moment of the magnet, and heat treating the magnet within a second magnetic field to form elongated grains from the second alloy and align the elongated grains with the moment.

A method includes mixing first and second alloys to form a mixture, pressing the mixture within a first magnetic field to form a magnet having anisotropic particles of the first alloy aligned with a magnetic moment of the magnet, and heat treating the magnet within a second magnetic field to form elongated grains from the second alloy and align the elongated grains with the moment.

The present invention relates to a method for producing a group III compound substrate, including: a base substrate forming step for forming a group III nitride base substrate by a vapor phase synthesis method; a seed substrate forming step for forming a seed substrate on the base substrate; and a group III compound crystal forming step for forming a group III compound crystal on the seed substrate by a hydride vapor phase epitaxy method. The group III compound substrate of the present invention is produced by the method for producing a group III compound substrate of the present invention. According to the present invention, a large-sized and high-quality group III compound substrate can be obtained at a low cost while taking advantage of the high film formation rate characteristic of the hydride vapor phase epitaxy method.

Provided is a cladded single crystal sapphire optical fiber. In one embodiment, the innovation provides a method for forming a cladding in a single crystal sapphire optical fiber by reactor irradiation. The reactor irradiation creates ions external to the fiber that enter the fiber, displace atoms in the fiber, and are implanted in the fiber, thus modifying the index of refraction of the fiber near the surface of the fiber and creating a cladding in the sapphire fiber.

Provided is a cladded single crystal sapphire optical fiber. In one embodiment, the innovation provides a method for forming a cladding in a single crystal sapphire optical fiber by reactor irradiation. The reactor irradiation creates ions external to the fiber that enter the fiber, displace atoms in the fiber, and are implanted in the fiber, thus modifying the index of refraction of the fiber near the surface of the fiber and creating a cladding in the sapphire fiber.

A device includes a semiconductor substrate containing gallium nitride and having a crystal face inclined from 0.05 to 15 inclusive with respect to the c-plane. The semiconductor substrate includes an irregular portion on the crystal face, and the contact angle of pure water having a specific resistance of 18 M.Math.cm or more on the surface of the irregular portion is 10 or less.