Nanoparticle formation from supersaturated carbon vapour generated by laser photolysis of carbon suboxide
In: J. Phys. D: Appl. Phys., Jg. 39 (2006) ; Nr. 20, S. 4359-4365
Zeitschriftenaufsatz / Fach: Maschinenbau
Particle formation and growth from condensation of supersatd. carbon vapor was investigated. At. carbon vapor was generated under well-controlled conditions from UV-laser pulse photolysis of C3O2 at 193 nm. Particle formation and growth were studied in a wide range of conditions with varying carbon vapor concn., bath gas compn., and pressure. The formation of particulate matter was obsd. as a function of time by laser light extinction. Particle sizes were detd. in situ by time-resolved laser-induced incandescence and ex situ by transmission electronic microscopy. The characteristic time of particle growth was 20-1000 micro s. The final particle size was 5-12 nm, increased with pressure, and depends on bath gas compn. We propose a simple model for the description of carbon vapor condensation that assumes condensation of individual atoms on the cluster surface as the main growth mechanism. The comparison of expts. and simulations provides information about the initial concn. of carbon clusters for the different mixt. conditions.