Deposition of zinc oxide/vanadium pentoxide composite thin films by thermionic vacuum arc plasma

Abstract

The study involved the deposition of Zinc oxide/vanadium pentoxide (ZnO/V₂O₅) composite thin films on the glass substrates using the Thermionic Vacuum Arc (TVA) plasma process. Three methods were employed: (1) ZnO and V₂O₅ powders were mixed in a 50:50 molar ratio, and plasma was generated in the same crucible (V + Z), (2) V₂O₅ plasma was deposited first, followed by ZnO (VZ), and (3) ZnO plasma was deposited first, followed by V₂O₅ (ZV). These deposition processes were performed entirely within the TVA system without removing the samples from the vacuum environment. This approach significantly reduced the risk of contamination and minimized processing time compared to conventional techniques. The structural, elemental, surface morphological, optical, and antibacterial properties of the deposited thin films were extensively investigated. The thin films exhibited primarily amorphous structures with some crystalline formations. Optical analysis revealed a single bandgap of 3.63 eV for the V + Z sample, while VZ and ZV samples displayed dual bandgaps (2.40 eV & 3.48 eV for VZ; 2.48 eV & 3.15 eV for ZV). Antibacterial tests showed that VZ and ZV thin films had superior activity, completely inhibiting Staphylococcus aureus and Escherichia coli after 2 h, compared to the lower inhibition observed with V + Z films. These findings demonstrate the potential of ZnO/ V₂O₅ composite thin films, particularly layered structures, for applications requiring enhanced antibacterial properties.