engleski

LASER ANNEALED ALUMINIUM NANOPARTICLE PRODUCTION

Aluminium nanoparticles are good candidate for light absorption enhancement in future photovoltaics. When embedded in the photoactive layer of bulk heterojunction, they enhance efficiency of photovoltaic devices. Such a doping with plasmonic nanoparticles improves power conversion efficiency so that it can exceed 20%. However, this improvement calls for good control of size and space distribution, that is sometimes achievable at prohibitevely high temperatures, that tend to damage the heterojunction structure itself. Therefore, laser annealing is alternative mode creating plasmonic nanoparticles, avoiding the need for excesive temperatures in photovoltaic production. Here we report the study of laser annealed aluminium nanoparticle production. Rather smooth Al films have been produced on monocrystalline silicon by magnetron sputtering at room temperature. The nominal thickness was 5 and 10 nm. These films have been laser annealed by pulsed infra red and ultra violet laser. Number of pulses varied from 1000 to 10 000, and single pulse energy from 70 to 200mJ. Atomic force microscopy (AFM) was used to study nanoparticle formation, their size distribution and uniformity of irradiated surface. It was found that larger number of pulses resulted in sharper size distribution, while the actual sizes, (both width and height of particles), and distribution widths varied substantially with film thickness and pulse energy. Several parameter combinations also resulted in bimodal size distribution.

laser annealing; aluminum nanoparticles

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