Production of metal-oxide nanoclusters using inert-gas condensation technique

Abstract

Inert-gas condensation is a novel technique that can be used to produce nanoclusters for different applications. In the present work, dc sputtering combined with inert-gas condensation were used to produce copper oxide nanoclusters inside an ultra-high vacuum compatible system. The size and yield of nanoclusters could be controlled by adjusting the inert-gas flow rate, sputtering discharge power, and aggregation length. The results revealed that nanoclusters were formed as a result of either or both mechanisms: three-body and two-body collisions. Herein, the three-body collision mechanism is responsible for nanocluster seed production, while two-body collision mechanism is responsible for nanocluster growth through atomic condensation and coagulation of nanoclusters. The inert-gas flow rate was found to be the main factor to determine the nanocluster size. The results were compared with a discrete coagulation system model and revealed reasonable agreement. Thin film of copper oxide nanoclusters was fabricated and used to produce a device. Electrical and optical measurements of the device revealed its suitability for practical applications such as solar cells.