"METAL-POLYMER NANOCOMPOSITES OBTAINED BY COMBINED PLASMA TEHNIQUES"
TE_229

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Stage II. Investigation of species present in polymerization plasma (PECVD) and in magnetron sputtering plasma (PVD); Synthesis, by means of sequential PECVD/PVD deposition, of metal-polymer nanocomposites materials with controlled surface plasmon resonance frequency, using various metals

 

Representative images associated to the results obtained in the second stage of TE_229 project:

Schematic of the experimental set-up for the synthesis of metal-polymer composites and plasma diagnostics

# Experimental set-up for the metal-polymer composite consists in a stainless steel vacuum chamber provided with a magnetron sputtering source and a PECVD plasma source;
# The sources are mounted perpendicular one to each other, and respectively at 45 degrees in respect to the substrate;
# The setup allows the sequential or simultaneous substrate exposure to the PVD plasma source and to the PECVD plasma source;
# The system includes mounting on perpendicular port of mass spectrometer head, Langmuir probes and optical fiber slots for Optical Emission Spectroscopy.

 

# Topographical and morphological investigations of the copper-polythiophene reveal the formation of core-shell type structures consisting of nanometer sized Cu nanoparticles coated with a thin polythiohene layer.
# Spectroscopic ellipsometry measurements followed by model fiting of the Cu-PPTh composites show a strong absorption peak around 740 nm, associated with the surface plasmon resonance effect due to the presence of Cu nanoparticles in the plasma polymer matrix

 

# Typical MS spectrum of the Ar/C₄H₄S mixture presents the expected cracking pattern of the thiophene inside the mass spectrometer with major peaks corresponding to C₄H₄S (84 amu), C₂H₂S (58 amu) and CHS (45 amu),
the Ar – related peaks at 40 and 20 amu Ar neutrals; once the plasma is ignited, the appearance of completely new formed species, as CS₂ at 76 amu is obvious;
# The mass spectra signal of ions associated to the masses higher than that of thiophene (C₂H₃S₂+ (91 amu), C₄H₄S₂+ (116 amu), etc).proves oligomerization reactions in the plasma volume;
# Monomer depletion was calculated for the prominent mass signals; a sharp increase of the monomer depletion immediately upon plasma ignition (1-3 W) and a much slighter

 

Dependence of the Ar and Cu abundances in the mass spectra as function of the applied RF power masses

# Ar peak (40 amu) and Cu peaks (63 and 65 amu) dominated the mass spectra of the plasma generated by the magnetron plasma source;
# Ar neutrals present a maximum intensity around 100 W applied RF power;
# Cu neutrals show a maximum intensity around 110 W applied RF.