Dust particles in low-pressure plasmas: Formation and induced phenomena

Abstract

Formation of dust particles is a common mechanism in low-pressure plasmas. These big particles (in comparison with other plasma species) are sometimes the desired final products of the process, but they may also constitute a severe drawback in certain contexts. In either situation, it is necessary to understand growth mechanisms well, in order to control or avoid dust particle formation. One of the problems that has to be overcome is that dust particle growth is usually a continuous mechanism: once started, it can enter into a cyclic regime where new generations of dust particles are succeeding one after the other. This cyclic phenomenon often induces a side effect consisting of instabilities of a few tens of Hz. This paper discusses the main characteristics of dust successive generations, and particularly the importance of dust-free spaces (void) involved in this process. Finally, some aspects related to deposition when several generations coexist will be presented.

Plasma inhomogeneities near the electrodes of a capacitively-coupled radio-frequency discharge containing dust particles

“…In laboratory reactors, there are many methods to create dust particles, mainly using reactive gases [8][9][10][11][12][13][14]o r material sputtering [15][16][17][18]. In the present work, material sputtering is used to grow a high density of sub-micron dust particles.…”

Carousel Instability in a Capacitively Coupled RF Dusty Plasma

“…Dust particles can be grown inside a plasma by gas phase reactions [1][2][3] that lead to high densities of submicron dust particles. These particles acquire a negative charge and when the global charge they represent is no more negligible compared with the electron density, a wide variety of low frequency instabilities are observed.…”

Nanoparticle forming reactive plasmas: a multidiagnostic approach

“…Taking into account the transient nature of the shoulder and other reports [101][102][103] one can explain the formation of the second generation as follows. At first a void forms inside the discharge.…”

“…It has indeed been shown that nanoparticles only nucleate in areas of the discharge with a sufficiently low number 200 nm density of nanoparticles, like voids, i.e. particle free volumes inside the discharge [101][102][103]. A reduced nucleation rate leads to a lower number density of nanoparticles in the discharge.…”