The invention relates to a method for obtaining a nanostructured layer of titanium nitride by deposition by cathode sputtering of a substrate at ambient temperature, characterised in that it comprises: - a first step of reactive cathode sputtering at ambient temperature in a vacuum chamber comprising a reactive gas, an inert gas, the substrate with a diameter of 100 mm or more, and a target cathode, under specific conditions; - a second step of wet etching of the monolayer of titanium nitride deposited during the first step, the wet etching comprising the application of a solution, in order to obtain a thin monolayer of titanium nitride, TiN, having controlled black coloration, the reactive cathode sputtering being carried out during the first step using a discharge provided by a direct current generator, the reactive gas being composed of nitrogen, with a predetermined flow rate of inert gas and of reactive gas entering the chamber, a predetermined ratio of inert gas and of reactive gas, a predetermined pressure in the chamber and a predetermined power of the direct current generator. Varying these parameters or not adhering to the ratio no longer provides the nanostructuring obtained in step 2.