화학공학소재연구정보센터
Thin Solid Films, Vol.355-356, 513-517, 1999
Interesting optical properties of films composed of very small grains formed from a high-rate nanoparticle beam
Only a few films have been deposited from nanoparticle beams in spite of interest dating back to the early 1970s. Early attempts did not condense, could only condense a few high vapor pressure solids, or were so low rate as to make growth too slow to be of use. A new type of high-rate deposition system overcomes these impediments. Deposits have been made using Cu targets for a 1 Torr argon + helium sputtering and condensation atmosphere followed by nozzle aperture extraction. The beam is highly non-uniform with maximum intensity on-axis, which drops rapidly to zero from one to a few degrees off-axis depending on source conditions. The work reported here explores soft-landed nanoparticle films using no acceleration. These soft-landed films are porous with nanocrystalline structure from about 5 to 10 nm crystallites. Films are optically transparent with a controlled air leak into the source chamber and contain a significant (tens of percent) carbon contamination following exposure to air. Optical properties of the films change with deposition conditions and are different than that of literature values of thin film copper. Atomic force microscopy study shows a very rough outer surface and isolated 5-10 nm nanoparticles in the nearly film free regions.