Optimization of excimer laser modification of silicon-nanoparticle layers using one-dimensional temperature simulations

One-dimensional temperature simulations were conducted in COMSOL Multiphysics® to investigate the temperature distribution during UV excimer laser modification of silicon-nanoparticle layers on metalized substrates. Typically, this laser modification leads to a self-organized transformation of the silicon-nanoparticle layer into crystalline μ-cone shaped silicon structures, which offer great potential for printed flexible electronics. The temperature simulation was adapted to the experiment by determining and incorporating process-relevant material properties. The good agreement between simulation and experimental results verifies that the highly complex structure of the porous silicon-nanoparticle layer can be well approximated with the applied effective-medium approach. The temperature simulation was used to determine the minimum required laser energy density for silicon μ-cone formation for different silicon-nanoparticle layer thicknesses. Thus, a reduction of the thermal load on the substrate can be achieved, enabling the laser modification of silicon-nanoparticles on flexible substrates with a limited temperature budget. As a proof-of-principle, the formation of silicon μ-cones on a flexible metalized polymer substrate is exemplarily shown.