科研之友
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摘要
A general method for reducing interparticle gap size in lithographically patterned metal particle arrays is introduced. Dense gold nanoparticle arrays are fabricated by electron beam lithography and the patterned structure is subsequently covered with thin layers of gold and annealed at a high temperature. This results in ripening of the initially patterned particles and in reduced interparticle distances, as well as in an improvement in the optical properties through gold recrystallization and grain growth. At intermediate processing steps, a distinctly bimodal particle distribution can be realized for effective nanofocusing of incident radiation into a high density of hotspots. 3D finite-difference time domain simulations and surface-enhanced Raman scattering experiments confirm that high local electric fields arise in such structures, resulting in enhancement of the Raman signals on the order of 10(6). This combination of lithographic patterning and self-assembly can be used to obtain novel plasmonic nanostructures that cannot be directly fabricated by other means.
- 出版日期2013-4
