Nanowires with controlled sizes formed by single ion track reactions in polymers

Abstract

Irradiation of polystyrene and polysilane derivatives by ion beams at MeV energies creates nanowires by causing cross-linking reactions within each ion track. The sizes of the cross-section of nanowires were found to depend on the LET (linear energy transfer), molecular weight, and cross-linking efficiency of the target polymer. The nanowires produced were transformed to elliptical shapes on the Si substrate after a solvent development process. The degree of the transformation changed with the molecular weight of the polystyrene derivatives. The degree is discussed in terms of the stiffness of the backbone of the target polymer materials, showing good correlation with the characteristic ratio of the polymer chains ( C ∞). This single particle nano-fabrication technique has a potential to produce polymer nano-structures with controlled size of the order of molecular sizes.