Abstract: Provided is an electrode material for secondary batteries, including a porous carbon material being derived from a plant and having an average particle size of less than 4 ?m.

Abstract: A semiconductor device comprising a substrate made of a material with a hexagonal crystal structure and having a substrate axis which is perpendicular to a principal surface of the substrate; and a nitride-based group III-V compound semiconductor layer grown directly on and in contact with the principal surface of the substrate without growing a buffer layer between the substrate and the nitride-based group III-V compound semiconductor layer, wherein, a direction of a growth axis of the semiconductor layer is substantially the same as a direction of the substrate axis of the substrate.