Analytical description of the film thickness distribution obtained by the pulsed laser ablation of a monoatomic target: Application to silicon and germanium

In this work, the spatial distribution of laser-generated species in vacuum from a monoatomic target is deduced from the analytical resolution of the hydrodynamic equations for a plasma expanding in the adiabatic regime. The thickness distribution of the laser deposited layers is demonstrated to be related to the initial dimensions of the plasma but independent of both the laser fluence and the atomic mass of the target element. From these calculations, we also deduced an angular distribution of the deposits as a sum of cos(n) theta. These theoretical results are experimentally supported in the specific case of the pulsed excimer laser ablation of Si and Ge monoatomic targets.