Characterization of cyclic dust growth in a low-pressure, radio-frequency driven argon-hexamethyldisiloxane plasma

Abstract

In a dusty plasma, nanometer-sized solid dust particles can be grown by the polymerization of plasma species from a reactive precursor gas. This type of plasma can be found in large-scale astrophysical objects, as well as in semiconductor manufacturing and material processing. In a laboratory environment, the plasma parameters can be carefully controlled and the dynamics of dust growth as well as the interaction between the plasma and the dust can be studied. In this work, we investigate the cyclic growth of dust particles in a low-pressure, radio-frequency driven argon-hexamethyldisiloxane (Ar-HMDSO) plasma using a multitude of diagnostics in a time-synchronized fashion. The combination of microwave cavity resonance spectroscopy (MCRS), plasma impedance measurements, laser light scattering, laser light extinction measurements and optical emission spectroscopy offers a broad view on the temporal behavior of the plasma in concert with the plasma-grown dust particles. We have studied the variation of several discharge parameters such as plasma power and HMDSO content. Therefore, this multi-diagnostic approach contributes to the fundamental understanding of the mechanisms behind dust growth in low-pressure plasmas.

Temporal afterglow between two pulses of repetitively pulsed argon-acetylene plasma: measuring electron and negatively charged species densities

“…The research path in this article can be extended to spatiotemporal afterglows of repetitively pulsed dust-forming plasmas. Once the multi-mode microwave resonance spectroscopy [60] is combined with LIP, the evolution of electrons and negatively charged species in different regions of the plasma in a cavity can be studied spatially and temporally resolved. density just before the onset of the afterglow phase is observed for the 1 s plasma-on time.…”

“…Dust particles are often externally injected into plasma environments, but can also be spontaneously formed when plasmas are ignited in reactive gases such as silane [12], hexamethyldisiloxane [13], methane, and acetylene [14]. In general, the spontaneous formation of dust particles inside an (often radio frequency (RF) driven) low-pressure plasma can be described by several stages and begins with the polymerization stage [15].…”

Time-Synchronized Microwave Cavity Resonance Spectroscopy and Laser Light Extinction Measurements as a Diagnostic for Dust Particle Size and Dust Density in a Low-Pressure Radio-Frequency Driven Nanodusty Plasma

“…The decreasing growth cycle time is a direct result of a change in the force balance acting on the particles. By increasing the plasma power, both the densities and the electric field strength increase, which eventually causes the ion drag force to be able to overcome the electrostatic force at shorter timescales [36]. This leads to a shorter growth cycle, which translates to a shorter residence time of the dust particles in the plasma and eventually leads to smaller dust particles.…”

“…In this type of dusty plasmas, dust particles are chemically grown in the plasma by means of admixing a reactive precursor gas with a noble background gas. For this, organic precursors (such as acetylene (C 2 H 2 ) [32] or methane (CH 4 ) [33,34]), silicon-based [35], or organosilicon precursor gases [36,37] are often used. Such precursor gases easily dissociate into fragments, after which these fragments efficiently polymerize into larger species.…”

“…This work can be seen as a follow-up after our previous work [36]. The basis of the experimental setup and the primary data set is the same, but the focus is on the development of the fitting method.…”