Differences in shapes of nanometric pores synthesized in olivine by swift heavy ion irradiation and etching along various crystal axes

Abstract

Recent atomic-scale simulations of swift heavy ion track etching in olivine predicted formation of nanopores with non-circle cross sections which shape may be controlled by the irradiated crystal orientation relative to the beam direction. Taking this into account, we developed a technique of such nanopores synthesis based on the precise etching time control. The approach includes the following steps: (a) orientation of the crystal relative to the SHI beam and irradiation; (b) selection of the track etching time most favorable for production of the pores with required dimensions; (c) removal of the surface layer containing etching pits in order to study the shape of narrow pores in the bulk. The atomic force and scanning electron microscopy confirm appearance of narrow polygonal channels in the irradiated and etched olivine crystals, which shapes depend on the crystallographic orientation.