Antibacterial Performance of Nanostructured Copper Nitride Thin Films

Objectives: To prepare nanostructured copper nitride (Cu3N) films at different substrate temperatures, and to assess the antibacterial properties. Methods: Nanostructured copper nitride (Cu3N) films are prepared at different substrate temperatures (303K to 573K) by the dc reactive magnetron sputtering technique on glass substrates and characterized with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), UV-Vis-NIR double-beam spectrophotometer and Pseudomonas aeruginosa (P. aeruginosa). Findings: As the substrate temperature increased from 303 to 573K, the deposition rate diminished from 17.8 to 10.9 nm/min. The films deposited at room temperature (303K) exhibit a microstructure characterized by island-like features. As the substrate temperature reaches 473K, a significant transformation occurs, resulting in the films achieving a highly compact and uniform microstructure, characterised by well-defined nanorods. The optical transmittance of the films increased from 62% to 74% with the increase of substrate temperature from 303 to 473 K. The nanostructured Cu₃N films show notable antibacterial properties against Pseudomonas aeruginosa. Novelty: The present obtained nanostructured Cu3N films are thermally stable even at 473K and exhibited significant antibacterial properties against Pseudomonas aeruginosa. Keywords: Thin films, Nanostructured, Sputtering, Copper nitride, Antibacterial properties