Synthesis of nanoparticles in RF discharge to study charging processes in plasma

Nanoparticles in a gas-discharge plasma environment can grow during the etching/deposition or can be deliberately generated to produce particles with desired characteristics. Understanding particle charge and charging dynamics is crucial for optimizing synthesis processes and studying particle-plasma interactions in nano-dusty plasmas. Laser-stimulated electron photodetachment (LSPD) is a method that enables in situ measurement of particle charge provided that the precise shift in electron density can be measured and other particle properties such as size and density are known. To study the LSPD from nanoparticles in dusty plasmas the growth of the carbonaceous particles in capacitively coupled radio frequency (CCRF) discharge from argon/acetylene mixture was adjusted for different gas mixture ratios. The dust particle growth dynamics were monitored by the discharge DC self-bias voltage measurements and optical emission spectroscopy. The light emission signal matches with the self-bias voltage changes indicating the cyclic growth nature of nanoparticles. Scanning electron microscopy of collected nanoparticles after several cycles of growth reveals the formation of amorphous carbon nanoparticles and agglomerates with sizes up to ~700 nm. The synthesized particles in the plasma environment will be used for the demonstration of LSPD-based real-time in-situ diagnostics in a couple with Laser-induced incandescence.