Emission spectroscopy analysis of carbonaceous molecules involved in dust particle growth by plasma
Résumé
Dusty plasmas are found in many astrophysical environments such as comet tails, planetary nebulae and rings or in fusion devices like the future ITER. In industrial and laboratory reactors, these dust particles become a huge problem, particularly in microelectronics. However, these particles could be used in many industrial applications related to nanotechnology. So it’s important to study the production of these solid particles.
In GREMI laboratory, several methods are used to create dust particles in a plasma. They are mainly based on reactive gases or material sputtering. In this work, experiments are performed in a capacitively-coupled RF discharge in the PKE-Nefedov reactor, where dust particles are grown by sputtering a polymer layer in Ar or Kr plasmas. The polymer layer is previously deposited on the electrodes. Dust particle growth is analyzed by using optical emission spectroscopy in order to study more precisely the spatial and temporal evolutions of the molecules involved in this process like: C2, CN, CH, CO. When dust particles are growing in the plasma, a laser at 685 nm is also used to highlight their presence. Their localization is determined by recording the scattered light with the spectrometer. Other tools are used to follow dust particle growth like a CCD camera and measurements of the discharge current.