Methods for fabricating a piezoelectric device are provided. The methods can include providing a substrate and forming a nanocrystalline diamond layer on a first surface of the substrate. The methods can also include depositing a piezoelectric layer on a first surface of the nanocrystalline diamond layer.

A semiconductor device including a graphene layer and a method of manufacturing the same are disclosed. A method in which graphene is grown on a catalyst metal by a chemical vapor deposition or the like is known. However, the graphene cannot be used as a channel, since the graphene is in contact with the catalyst metal, which is conductive. There is disclosed a method in which a catalyst film (2) is formed over a substrate (1), a graphene layer (3) is grown originating from the catalyst film (2), an electrode (4) in contact with the graphene layer (3) is formed, and the catalyst film (2) is removed.