Abstract Spectrally selective NiC films have been produced by reactive sputtering of Ni in an argon-methane gas mixture. Depending on the substrate material, films sputtered at a methane pressure of about 0.15 Pa exhibit a moderate solar absorptance (0.80–0.90) and an extremely low emittance (0.028–0.045 at 150°C). These selectively absorbing films consist of small Ni particles embedded in an electrically insulating amorphous carbon matrix. Since these films are found to be stable up to more than 400°C in vacuum, they are well suited for application in high performance evacuated collectors. The first part of this paper discusses the structure and the electrical properties of these films. The second part of this paper will discuss the optical properties, in particular the spectrally selective behaviour.