Ultra-short pulsed laser for nano-texturization associated to plasma immersion implantation for 3D shallow doping: Application to silicon photovoltaic structures.

It has been recently shown (Mazur et al) (1-7) that a simple way to improve the photocurrent of a silicon-based solar cell is to irradiate the silicon surface with a series of femtosecond laser pulses, in the presence of a sulfur containing gas. This improves the formation of micro- spikes on the silicon surface that strongly reduces the reflectivity of the illuminated surface for the incident solar light (Black Silicon). We have prepared photovoltaic structures with different nano-texturization obtained by means of a femtosecond laser, without the use of corrosive gas (under vacuum). To take in account the 3D structured front surface, the emitter doping has been realized by using Plasma Immersion Ion Implantation (so-called PULSION). The results show a photocurrent increase of about 30 % in the laser textured zones.