Multiband and Ultrahigh Figure-of-Merit Nanoplasmonic Sensing with Direct Electrical Readout in Au-Si Nanojunctions.

Wen, Long; Liang, Li; Yang, Xianguang; Liu, Zhong; Li, Baojun; Chen, Qin · ACS Nano · 2019

basic_science · Level V

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Abstract

Nanoplasmonic sensors are heralding exciting advances as clinical diagnostics as they facilitate label-free, real-time, and ultrasensitive monitoring in a small footprint. But in essence, almost all of them still largely rely on expensive and bulky spectroscopy/imaging instrumentation and methodology, which has become the major impediment for point-of-care (POC) testing implantation. In this context, an ultracompact optical sensor is achieved with direct electrical read-out capacity by combining plasmonic sensing resonance and optical-signal-transducing into a unity integrated device. Benefiting from the convergence of high figure-of-merit (∼190) resonance and hot electron enhanced photoelectric conversions on the near-flat Au-Si nanotrench framework, the device is demonstrated to yield a detection limit on the order of 10<sup>-6</sup> RIU in a broadband operating wavelength window (700-1700 nm). Such a compact, silicon process compatible, and ultrasensitive optoelectronic sensing platform holds great potentials for future clinical POC detection and on-chip microspectrometer applications.