Anodic arc discharge: Why pulsed?

Pulsed anodic arc discharge is a novel synthesis method of nanomaterials by means of low-temperature atmospheric plasma. The technique consists in periodically supplying DC power to two vertically aligned electrodes in the form of short unipolar pulses with peak currents of a few hundred Amperes in a helium atmosphere. The pulsed arc plasmas are sustained at frequencies on the order of 1 Hz with around 10% of duty cycle. It constitutes a versatile technique thanks to a series of advantages compared to continuous DC arc processes, in particular, flexibility in the experimental conditions, process stability and repeatability, better utilization of ablating anode material, lower production of macroparticles, and lower thermal loads. Such features are discussed in this article. A brief overview concerning the recent accomplishments of pulsed arc discharge on deposition of carbon nanostructures (graphene and carbon nanotubes) and few-layer flakes of molybdenum disulphide and an outlook on future applications of this method for the discovery of new materials with tailored functional properties are provided.