Photoresistance Switching of Plasmonic Nanopores

Abstract

Fast and reversible modulation of ion flow through nanosized apertures is important for many nanofluidic applications, including sensing and separation systems. Here, we present the first demonstration of a reversible plasmon-controlled nanofluidic valve. We show that plasmonic nanopores (solid-state nanopores integrated with metal nanocavities) can be used as a fluidic switch upon optical excitation. We systematically investigate the effects of laser illumination of single plasmonic nanopores and experimentally demonstrate photoresistance switching where fluidic transport and ion flow are switched on or off. This is manifested as a large (∼1–2 orders of magnitude) increase in the ionic nanopore resistance and an accompanying current rectification upon illumination at high laser powers (tens of milliwatts). At lower laser powers, the resistance decreases monotonically with increasing power, followed by an abrupt transition to high resistances at a certain threshold power. A similar rapid transition, although at a lower threshold power, is observed when the power is instead swept from high to low power. This hysteretic behavior is found to be dependent on the rate of the power sweep. The photoresistance switching effect is attributed to plasmon-induced formation and growth of nanobubbles that reversibly block the ionic current through the nanopore from one side of the membrane. This explanation is corroborated by finite-element simulations of a nanobubble in the nanopore that show the switching and the rectification.

Self-Aligned Plasmonic Nanopores by Optically Controlled Dielectric Breakdown

“…Reports on plasmonic nanopores have so far mostly focused on nanoplasmonic heating. 25–27 However, great promise lies in also exploiting the capabilities of these plasmonic nanostructures for extreme light-concentration to local nm-sized hotspots. Indeed, first examples of plasmon-enhanced optical detection of translocating analytes are already at hand.…”

Nanopore Sensing

“…246 In Figure 6d, the schematic of the “pore-in-cavity” plasmonic system and TEM image of the cavity and nanopore are shown. In this method, the free-standing SiN x membrane at the bottom of a gold nanoslit was fabricated via alternative chemical vapor deposition (CVD) of SiN x , Au, and SiN x again; the nanopore is then drilled into the membrane by TEM.…”

“…Magnified TEM image of red dashed circle in middle panel, showing a typical 10 nm nanopore inside the gold nanocavity (right). Reproduced from Li, Y.; Nicoli, F.; Chen, C.; Lagae, L.; Groeseneken, G.; Stakenborg, T.; Zandbergen, H. W.; Dekker, C.; Van Dorpe, P.; Jonsson, M. P. Nano Lett 2015 15 , 776–782 (ref 246). Copyright 2015 American Chemical Society.…”

“…(Bottom) Current–voltage curves that highlight rectification effects of high powered laser illumination. Reproduced from Li, Y.; Nicoli, F.; Chen, C.; Lagae, L.; Groeseneken, G.; Stakenborg, T.; Zandbergen, H. W.; Dekker, C.; Van Dorpe, P.; Jonsson, M. P. Nano Lett 2015 15 , 776–782 (ref 246). Copyright 2015 American Chemical Society.…”

Raman fingerprinting of single dielectric nanoparticles in plasmonic nanopores

“…For fluorescence detection, the locally enhanced field is exploited to detect molecules and particles in small volumes 12 . They are metallic nanoapertures placed on a free standing membrane with a tiny hole 3,[11][12][13][14][15][16][17][18][19][20][21][22] . Plasmonic nanopores allow the use of more techniques to study the kinetics.…”