10.1021/nn2025868.s001
Huigao Duan
Huigao
Duan
Hailong Hu
Hailong
Hu
Karthik Kumar
Karthik
Kumar
Zexiang Shen
Zexiang
Shen
Joel K. W. Yang
Joel
K. W. Yang
Direct and Reliable Patterning of Plasmonic Nanostructures with Sub-10-nm Gaps
American Chemical Society
2011
application
ultrasmall gaps
plasmonic structures
lithography
tunable plasmonic nanostructures
nm
pattern
SERS
HSQ
method
fabrication
2011-09-27 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Direct_and_Reliable_Patterning_of_Plasmonic_Nanostructures_with_Sub_10_nm_Gaps/2611288
Nanoscale gaps in metal films enable strong field enhancements in plasmonic structures. However, the reliable fabrication of ultrasmall gaps (<10 nm) for real applications is still challenging. In this work, we report a method to directly and reliably fabricate sub-10-nm gaps in plasmonic structures without restrictions on pattern design. This method is based on a lift-off process using high-resolution electron-beam lithography with a negative-tone hydrogen silsesquioxane (HSQ) resist, where the resulting nanogap size is determined by the width of the patterned HSQ structure, which could be written at less than 10 nm. With this method, we fabricated densely packed gold nanostructures of varying geometries separated by ultrasmall gaps. By controlling structure sizes during lithography with nanometer precision, the plasmon resonances of the resulting patterns could be accurately tuned. Optical and surface-enhanced Raman scattering (SERS) measurements on the patterned structures show that this technique has promising applications in the fabrication of passively tunable plasmonic nanostructures with ultrasmall gaps.