Ion energy spread in laser-assisted atom probe tomography

A dedicated setup has been developed to measure with precision the appearance energy of field evaporated ions in laser-assisted atom probe. Energy spreads down to 0.5 eV can be measured on different materials under different experimental conditions (electric field and laser illumination). Looking at each possible contributions, we show that this energy spread depends on the material and that it is due to the field evaporation process itself and especially to temperature-induced surface diffusion and electric-field strength in the case of metals and low-band-gap materials. For large-band-gap materials, a dependence on the laser illumination is shown.