Nano-scale and surface precipitation of metallic particles in laser interference patterned noble metal-based thin films

摘要

Laser interference patterning (also known as "laser interference metallurgy") is used to locally tailor the microstructure of oxide (Pd_(0.25)Pt_(0.75)O_x) and nitride (Cu_3N) thin films to induce a chemical decomposition, which is responsible for a decrease of electrical resistivity. This technique allows hereby a laser-induced chemical decomposition of as-deposited oxide and nitride films, resulting locally in a porous microstructure due to the simultaneous emission of gaseous nitrogen and oxygen. The process locally generates at the nanometer scale metal precipitatation of Pt or Cu in the oxide or nitride matrix. Thus, isolated metallic clusters with low resistivity coexist with a high resistivity phase, establishing a preferential electrical conduction path and giving the system a lower effective resistivity. The decomposition process is investigated by four-point probe method, X-ray diffraction, spectrophotometry, white light interference, scanning and transmission electron microscopies.