Abstract: A porous material comprising vapor grown carbon fiber in an amount of 10 to 90 mass %, fiber filaments of the carbon fiber forming a three-dimensional network and having a diameter of 1 to 1,000 nm, an aspect ratio of 5 to 15,000, a specific surface area (by BET method) of 2 to 2,000 m2/g, and the ratio of the intensity of the peak at 1,360 cm?1 in a Raman scattering spectrum of the carbon fiber to that of the peak at 1,580 cm?1 in the spectrum(I1360/I1580) is 0.1 to 2.0, wherein the porosity of the porous material (V/V0) is 0.50 to 0.99 and a specific surface area is 5 to 1,000 m2/g; and a production method and use thereof. The vapor grow carbon fiber impregnated in the porous material of the present invention does not contain aggregates and a three-dimensional network is formed between the fiber filaments, wherein length of each of the fiber filaments is maintained.

Abstract: A porous material comprising vapor grown carbon fiber in an amount of 10 to 90 mass %, fiber filaments of the carbon fiber forming a three-dimensional network and having a diameter of 1 to 1,000 nm, an aspect ratio of 5 to 15,000, a specific surface area (by BET method) of 2 to 2,000 m2/g, and the ratio of the intensity of the peak at 1,360 cm?1 in a Raman scattering spectrum of the carbon fiber to that of the peak at 1,580 cm?1 in the spectrum(I1360/I1580) is 0.1 to 2.0, wherein the porosity of the porous material (V/V0) is 0.50 to 0.99 and a specific surface area is 5 to 1,000 m2/g; and a production method and use thereof. The vapor grow carbon fiber impregnated in the porous material of the present invention does not contain aggregates and a three-dimensional network is formed between the fiber filaments, wherein length of each of the fiber filaments is maintained.

Abstract: A group III-V compound semiconductor doped with an impurity, having an undoped film of SiOx and a film for preventing the diffusion of Group V atoms (e.g., an SiN film) are formed on a crystal of Group III-V compound semiconductor in which the silicon in the SiOx film is diffused into the Group III-V compound semiconductor, thereby forming a doped layer.

Abstract: A method of doping a Group III-V compound semiconductor with an impurity, wherein after an undoped film of SiOx and a film for preventing the diffusion of Group V atoms (e.g., an SiN film) are formed in this order on a crystal of Group III-V compound semiconductor, the sample is subjected to at least one heat treatment to cause silicon in the SiOx film to diffuse into the Group III-V compound semiconductor, thereby forming a doped layer. Using this doped layer forming method, field-effect transistors, diodes, resistive layers, two-dimensional electron gas or one-dimensional quantum wires, zero-dimensional quantum boxes, electron wave interference devices, etc. are fabricated.