High-power impulse magnetron sputtering of a planar Ta target in various Ar + O-2 + N-2 gas mixtures was investigated at an average target power density close to 50 W cm(-2) during a deposition. A strongly unbalanced magnetron was driven by a pulsed dc power supply operating at the repetition frequency of 500 Hz and the average target power density of up to 2.4 kW cm(-2) in a pulse with a fixed 50 mu s duration. Si(100) and glass substrates were at a floating potential, and the substrate temperatures were less than 285 degrees C. A pulsed reactive gas (O-2 and N-2) flow control made it possible to produce high-quality Ta-O-N films of various elemental compositions with high deposition rates of 97-190 nm/min. The film compositions (in at.%) were varied gradually from Ta28O71 with less than 1 at.% of H to Ta38O4N55 with 3 at.% of H. The Ta27O40N31 films with 2 at.% of H, which were produced at the 50% N-2 fraction in the reactive gas flow with the highest deposition rate of 190 nm/min achieved, were nanocrystalline with an optical band gap of 2.5 eV and hardness of 8 GPa. These films with a shift of the absorption edge to 500 nm are potential candidates for application as visible-light driven photocatalysts. (C) 2014 Elsevier B.V. All rights reserved.