Further, as shown in FIGS. 16B and 17B, such material as Palladium (Pd), Niobium (Nb), Molybdenum (Mo), or an insulator of silicon nitride (SiN) film or silicon oxide (SiO2) film is deposited to form a growth preventing layer on the catalyst in the shape of the nanodots or the nanowires with a predetermined gap therebetween.