Laura Cacot1,2,Luc Stafford1,Nicolas Naudé2,Richard Clergereaux2
University of Montreal1,Laplace2
Laura Cacot1,2,Luc Stafford1,Nicolas Naudé2,Richard Clergereaux2
University of Montreal1,Laplace2
Aerosol-assisted plasmas can be used to produce a wide variety of thin films, including homogeneous, nanotextured and/or nanocomposite coatings. For example, the nebulization of colloidal solutions, <i>i.e.</i> liquid solutions containing nanoparticles, in plane-to-plane dielectric barrier discharge (DBD) at atmospheric pressure has been used for nanocomposite thin film deposition. However, nanoparticles-loaded droplets in the aerosol lead to the deposition of aggregated nanoparticles embedded in the matrix.<br/>Recently, a new process of nanoparticles injection in plasmas has been developed. This method consists in synthesizing the nanoparticles prior to their injection in the plasma in a low frequency pulsed injection regime. However, the impacts of the pulsed liquid injection on the DBD physics are still opening questions.<br/><br/>This work aims to study a pulsed-liquid-assisted DBD deposition process. In contrast with the continuous nebulization of solutions, pulsed injection causes a sudden increase of the quantity of precursor as droplets in the inter-dielectric space – the average velocity being in the 10 m.s<sup>-1</sup> range. We observed that depending on the process parameters (injection times, pulse frequency, continuous gas flow rate, etc.), the discharge stability is modified. These parameters are also critical for transport and evaporation of the droplets and so on the thin film deposition (here ppHMDSO). For example, by varying the different parameters of the pulsed-liquid-assisted DBD, we observe that the deposit can consist in different phases (liquid and solid) as a function of the time residency of the aerosol and the thickness of the deposited layer. Furthermore, the variation of the discharge frequency can also be a way to tailored the thin-film deposition. In that aim this parameter was change to obtain a operation diagram of the process and get a transition from misty to dusty plasma.