Gold/carbon superfine particles produced in pulsed CO2 laser stimulated plasmas

A new technique for the production of composite nano materials was used to produce carbon coated gold superfine particles in the 100 nm size range. Particles were produced in pulsed CO2 laser (2 J/pulse at 3×109 W/cm2 ) stimulated plasmas using solid Au targets and 1:3 mixtures of CH4, CO, or CO2 with He or H2 gases at 1.3 kPa pressure. The particle production rate was dependent on the presence and type of carbonaceous gas species, and the partial and total gas pressures. Thin films of the black superfine particles were deposited on glass, ceramic and metal substrates. X‐ray photoelectron spectroscopic analyses showed that Au was in the metallic state in the particles, both before and after thermal annealing, at an average concentration of 95% by mass. Fourier transform ion cyclotron resonance mass spectrometry of gaseous products emitted during thermal and laser anneals identified the major constituents as carbon dioxide and hydrocarbons. Scanning electron microscopy images of thermally annealed films sh...