Synthesizing aluminum nanoparticles using DC diode sputtering and gas aggregation cluster source

Aluminum nanoparticles (AlNPs) are promising materials for energy related applications such as photovoltaics and photocatalysis, and AlNPs are highly promising due to their optical tunability and abundance. Herein, a new gas aggregation cluster source has been developed to produce AlNPs with DC diode sputtering. The AlNPs size is affected by parameters such as pressure and diode current, enabling the formation of particles ranging from 10 to 300 nm in size with a wide size distribution. A thin oxide shell was identified on some particles. DC diode sputtering enhances target utilization, reducing the frequency of target replacements by sputtering from the entire surface of the target as opposed to the racetrack of typical magnetron sputtering schemes. In addition, the DC diode performs optimally at higher pressure compared to conventional magnetron sputtering methods. This allows a larger electrode gap to be maintained when used in a gas aggregation source, minimizing the buildup of sputtered material on the anode, which otherwise requires frequent disassembly and cleaning to prevent discharge instability and arcing. This method of depositing nanoparticles is particularly suited for photovoltaic applications as it is a vacuum-based technique that can offer seamless integration into the production process of standard silicon solar cells.