LAUSR

Abstract An open-source and full-3D Monte Carlo simulation code, Mat-TRIM, was developed in MATLAB to study the primary knock-on atom (PKA) statistics along nanowires under ion radiation. It is based on TRIM/SRIM’s physics; however, compared to TRIM/SRIM, it enables us to properly handle the 3D geometry of a cylindrical nanowire and a planar source of ions. In this paper, we first discuss the mechanism of Mat-TRIM, followed by some validation examples. Then the distributions of ion density, PKA density, PKA total energy, and PKA average energy in nanowires are explored. Significant differences have been found between the slab and the nanowire simulations. The relative error of a 1D slab and the assumption of a point beam source can be more than 1000% when the nanowire is around 20 nm in diameter. In addition, collisions with electrons is demonstrated to be the dominant mechanism of energy loss in narrow nanowires. Our results reveal that full-3D simulations which correctly treat ion leakage at sample boundaries are necessary to properly simulate PKA production in nano-sized targets.