Annealing Process in the Refurbishment of the Plasmonic Photonic Structures Fabricated Using Colloidal Gold Nanoparticles

Solution-processible fabrication techniques have been demonstrated with promising features for realizing different types of plasmonic devices, which combine interference lithography, spin-coating of the colloidal gold nanoparticles, and subsequent annealing process at a temperature of 200–300 °C. However, the resultant device needs to be improved in the following considerations: (1) The photoresist master grating needs to be removed for the applications in optoelectronic or sensor devices and (2) each lattice site of the photonic crystals is still composed of closely contacted gold nanoparticles. Actually, these metallic photonic structures can be refurbished through a further annealing process. Using an annealing temperature above 450 °C, we have successfully removed the remaining photoresist and make the gold nanoparticles join into a solid homogenous unit on each lattice site after being fully molten. Thus, high-quality gold nanostructures with excellent plasmonic response can be obtained. This accomplished an improved recipe for the solution-processible fabrication of plasmonic nanostructures. The corresponding devices with improved optical properties become more suitable for biosensors and optoelectronic devices.