Silicon Nanowire Bridge Arrays With Dramatically Improved Yields Enabled by Gold Colloids Functionalized With HF Acid and Poly-L-Lysine

Abstract

Nanowire bridges are attractive structures for characterizing nanowires without impairment during the postprocessing steps and fabricating high-performance sensors. In this study, arrays of silicon nanowire bridges were reproducibly fabricated using chemical vapor deposition in the confined regions of patterned silicon electrodes. While depositing gold colloids without additives resulted in a negligible number of nanowire bridges, treating the colloids with HF acid or functionalizing the silicon electrode surfaces with poly-L-lysine increased the yields to nearly 97%. This dramatic improvement in yield was a result of increased adsorption of Au nanoparticles to the electrode surface. We show that diluted colloids along with the electrode surface treatment increase the possibility of occurrence of bridges with fewer nanowires. Micrographs and current-voltage measurements showed robust electrical, mechanical and metallurgical connections of nanowire bridges to the electrodes during the growth process.