2D spatial control of metal nanoparticles by multi laser-lithography and heavy-ion irradiation

A new method for nanoparticle planar control has been proposed based on optical laser-lithography technique. With this method, the planar spatial resolution of the lithography is improved. Combining the lithography with subsequent ion-irradiation technique, a two-dimensionally (2D) patterned structure of Cu nanoparticles in a silica substrate is obtained with a sub-micrometer spatial resolution. The size of each “spot” is 500 × 500 nm2, and the pitch is 2 μm. Planar TEM image and the result of scanning near-field optical microscopy (SNOM) verify the nanoparticle 2D-patterned distribution. Further improvement of the processing may enable 2D nanoparticle patterning with a pitch on a sub-micrometer scale.