Tantalum Oxynitride Thin Films: Assessment of the Photocatalytic Efficiency and Antimicrobial Capacity

Abstract

Tantalum oxynitride thin films have been deposited by reactive magnetron sputtering, using a fixed proportion reactive gas mixture (85% N2 + 15% O2). To produce the films, the partial pressure of the mixture in the working atmosphere was varied. The characteristics of the produced films were analyzed from three main perspectives and correspondent correlations: the study of the bonding states in the films, the efficiency of photo-degradation, and the antibacterial/antibiofilm capacity of the coatings against Salmonella. X-ray Photoelectron Spectroscopy results suggest that nitride and oxynitride features agree with a constant behavior relative to the tantalum chemistry. The coatings deposited with a higher reactive gas mixture partial pressure exhibit a significantly better antibiofilm capacity. Favorable antibacterial resistance was correlated with the presence of dominant oxynitride contributions. The photocatalytic ability of the deposited films was assessed by measuring the level of degradation of an aqueous solution containing methyl orange, with or without the addition of H2O2, under UV or VIS irradiation. Degradation efficiencies as high as 82% have been obtained, suggesting that tantalum oxynitride films, obtained in certain configurations, are promising materials for the photodegradation of organic pollutants (dyes).

Experimental Investigation on the Sputtering Process for Tantalum Oxynitride Thin Films

“…Lastly, a tentative, non-quantitative comparison for the photodegradation of methylene orange between our results and a recent study in [46] can provide a clue on the efficiency of TaON films under visible light. Our results indicate that TaON by 0.5-1.5 sccm O2 degrades 14 to 29.5% of methylene orange, while it is reported around 10% for TaON under partial pressure 0.02-0.24 Pa of 85%N2 + 15%O2 gas mixture.…”

“…The gap between the two bands is within 1.87-2.08 eV. The amorphous tantalum oxynitride (Ta-O-N) films in [38] [46]. In fact, most tantalum oxynitrides have bandgaps between 1.9 and 2.5 eV [1, 3,47].…”

“…Our results indicate that TaON by 0.5-1.5 sccm O2 degrades 14 to 29.5% of methylene orange, while it is reported around 10% for TaON under partial pressure 0.02-0.24 Pa of 85%N2 + 15%O2 gas mixture. Reference [46] provides abundant results from various characterizations and tests for sputtered tantalum oxynitride films.…”

Preparation of Ta3N5 Nanosheet by Nitridation of Monolayer Tantalum Oxide Nanosheet

“…Metal nitride, oxynitride, and nitrogen‐doped materials have been intensively investigated for various applications including pigments, [1] antimicrobial capacities, [2] electrodecatalysts, [3] dielectrics, [4] optoelectronic materials, [5] and photocatalysts. As photocatalysts, particularly d0‐ or d10‐type oxynitride based on Ti 4+ , Nb 5+ , Ta 5+ , Zn 2+ , and Ga 3+ have band gape energy of 1.8‐2.1 eV, which absorb visible light at 600 to 700 nm, have been widely studied as a promising candidate for solar H 2 generation [6] .…”

Optical and Mass Spectra From Reactive Plasma at Magnetron Deposition of Tantalum Oxynitride

“…In the studies carried out in [1][2][3][4][5], the formation of coatings from ternary oxynitride structures TaO x N y was performed by the method of reactive magnetron sputtering at different flows of reactive gases, Oxygen and Nitrogen. In [1] photocatalytic and antibacterial properties of tantalum oxynitride obtained by the method of RF magnetron sputtering was investigated. In [2], the multiphase structure of stable (Ta 2 N, Ta 3 N 5 ) and metastable (TaN, Ta 4 N 5 , Ta 3 N 4 ) tantalum nitride compounds and its corrosion resistance were studied.…”