Refractive Index Sensor Based on Leaky Resonant Scattering of Single Semiconductor Nanowire

Abstract

Optical refractive index (RI) sensors, with the advantages of fast response, resistance to electromagnetic interference, and more options for signal collection, are widely used in biological fields. Compared with the metallic nanoparticle RI sensors based on localized surface plasmon resonance (SPR), nonmetallic nanomaterial RI sensors based on leaky resonant scattering have the advantages of high sensitivity, large sensing volume, good reliability, and more suitability for biosensing. However, so far studies on nonmetallic nanomaterial RI sensors are less reported. In this work, we study semiconductor nanowire (NW) RI sensors using a CdSe nanowire as an example. The NW diameter and substrate effects on the sensitivity of the RI sensors are investigated experimentally and theoretically. The bulk wavelength sensitivity of a suspended NW can be as high as 235 nm/RIU (per refractive index unit), and the highest figure of merit is 4.6. The larger decay length (∼100 nm) of the NW sensor enables greater sensing volume compared with a localized SPR sensor. Besides, we demonstrate that, by choosing proper diameter, we can tune the scattering efficiency peak into the optimum spectral region (600−900 nm) for biosensing. We also demonstrate that the semiconductor NW RI sensors have good reproducibility and reliability. Our work predicts that the semiconductor NW RI sensors have promising applications in diverse sensing devices, especially in biosensing.

Novel High-Sensitivity Racetrack Surface Plasmon Resonance Sensor Modified by Graphene

“…Compared with the graphene-free counterparts, the Q-factors with graphene of mode 1 and mode 2 increase by more than 0.4% and 17.3%, respectively. In addition, compared with 5.4 [ 12 ] and 4.188 [ 24 ], the highest Q-factor of the proposed plasmonic resonator sensor is 21.5, which is more than 5 times higher than previously reported values.…”

“…After that, a sensor based on nanohole arrays, with a sensitivity of 659 nmRIU −1 , was proposed by Cuevas et al [ 11 ]. A single semiconductor nanowire [ 12 ] and a simple metallic nanogroove array [ 13 ] were constructed, and their sensitivities reached 235 nmRIU −1 and 1200 nmRIU −1 , respectively. Recently, many research groups have combined photonic devices with graphene materials to establish a new research area called graphene nanophotonics [ 14 ].…”

Highly Sensitive Refractive Index Sensor Based on Polymer Long-Period Waveguide Grating With Liquid Cladding

“…Optical refractive index (RI) sensor exhibits many interesting properties including high sensitivity, fast response, wide dynamic range, multiplexing capability, remote sensing capability, freedom from electromagnetic interference, and capability to operate in harsh environments. A semiconductor nanowire RI sensor is demonstrated [1], and the sensitivity is as high as 235 nm/RIU (refractive index unit, besides, by choosing proper diameter, and the scattering efficiency peak can be tuned into the optimum spectral region (600 nm -900 nm) for biosensing. Optical fiber sensors based on the long-period fiber grating (LPG) are proposed for an RI sensor [2][3][4].…”

Measurement of Nanowire Optical Modes Using Cross-Polarization Microscopy

“…Earlier, scattered light and the subsequent characterization of optical modes from dispersed horizontal NWs have been studied with dark-field microscopy 17 – 19 . In comparison, here the optical modes are characterized directly from NW arrays vertically standing on the substrate without additional processing.…”