Achieving Continuous Sub-100-nm Plasmonic Nanowires as Long as Centimeters

Abstract

Gold nanowires with a width smaller than 100nm and a length in the order of centimeters have been fabricated using colloidal gold nanoparticles. The dewetting of the colloidal solution of gold nanoparticles on the photoresist master grating with a small duty cycle is utilized to limit the amount of gold nanoparticles that are confined into the grating grooves after spin-coating, which favors the achievement of narrow gold nanowires. During the subsequent annealing process, the sublimation of the ligands covering the gold nanoparticles, the melting of the gold nanoparticles, and the removal of the photoresist master grating take place sequentially as the annealing temperature is increased from room temperature to about 450oC. Thus, high-quality gold nanowires are produced with excellent continuity in a large scale and excellent plasmonic response. These kinds of structures are important for sensitive biosensors with flexible dynamics in both the dimensions and the spectroscopic response.