Polarized laser-induced plasmonic welding of copper-gold heterogeneous nanojunction for glucose sensor

Abstract

Cu nanomaterials have shown superior response speed and sensitivity to glucose sensors. Here, we demonstrate a polarized laser-induced plasmonic nanowelding technique to assemble Cu-Au heterogeneous nanojunction into glucose sensor. Our simulation results reveal that the localized surface plasmon resonance induced by laser with parallel polarization is located at the two ends of nanowire. Consequently, Cu nanowire assembled on Au pad pair is melted at the two ends and welded on two Au pads, thereby obtaining two Cu-Au heterogeneous nanojunctions. The current-voltage curves show that the plasmonic welded Cu-Au heterogeneous nanojunctions exhibit reliable ohmic contact with a contact resistance of about 100 Ω. In addition, the Cu nanowires did not suffer serious oxidative damage, because the oxidized Au-Cu heterogeneous nanojunctions form a Schottky contact. Experimental result shows that the plasmonic welded Cu-Au heterogeneous nanojunction has a high detection accuracy and response speed for glucose solutions. The minimum detection concentration and response speed are 1 × 10−6 mol/L and 0.8 s, respectively.