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Shadow Nanosphere Lithography. Peter J. Shin Department of Bioengineering. Introduction. A. Kosiorek, et al., Shadow Nanosphere Lithography: Simulation and Experiment, Nano Lett., 2004. Interested in Batch Fabrication technique for making biosensors (i.e. SERS substrate).
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ShadowNanosphereLithography Peter J. ShinDepartment of Bioengineering
Introduction • A. Kosiorek, et al., Shadow Nanosphere Lithography: Simulation and Experiment, Nano Lett., 2004 • Interested in Batch Fabrication technique for making biosensors (i.e. SERS substrate) • Wanted features include - low cost manufacturing - regular patterns in large area (6” Si wafer) - very high uniformity
Nanosphere Lithography (NSL) Metal (Au, Ag) Deposition • Metal deposit with electron beam evaporation (EBE) system • Control over shape & size of patterns by varying bead radius Array of Polystyrene Beads as Mask Si Substrate
Nanosphere Lithography (NSL) 1. Bead Coating (self-assembled monolayers) 2. Deposit Metal 3. Bead Removal (toluene, tape) Top View Side View
Nanosphere Lithography (NSL) Targeted Pattern scanning electron microscopy (SEM) image resulting from fabrication process (image from Van Duyne’s group)
Shadow Nanosphere Lithography * Modified EBE System • Sample • Metal source 5. e-beam source Θ : angle between sample & metal source α : angle of sample rotation
Shadow Nanosphere Lithography Sample Rotation α Varying α resulting in nanowire Metal (Au, Ag) Deposition Θ Varying Θ resulting in complex morphology
Shadow Nanosphere Lithography Conventional NSL vs Shadow NSL 150nm Cr with Θ = 25° + 15nm Ni with Θ = 0° Θ = 0° & α = 0° leads to conventional NSL