posted on 2024-02-22, 09:03authored byChao Zhang, Jibing Tan, Baoqiang Du, Chang Ji, Zhiyang Pei, Mingrui Shao, Shouzhen Jiang, Xiaofei Zhao, Jing Yu, Baoyuan Man, Zhen Li, Kaichen Xu
Actively
controlling surface-enhanced Raman scattering
(SERS) performance
plays a vital role in highly sensitive detection or in situ monitoring.
Nevertheless, it is still challenging to achieve further modulation
of electromagnetic enhancement and chemical enhancement simultaneously
in SERS detection. In this study, a silver nanocavity structure with
graphene as a spacer layer is coupled with thermoelectric semiconductor
P-type gallium nitride (GaN) to form an electric-field-induced SERS
(E-SERS) for dual enhancement. After applying the electric field,
the intensity of SERS signals is further enhanced by over 10 times.
The thermoelectric field enables fast and reproducible doping of graphene,
thereby modulating its Fermi level over a wide range. The thermoelectric
field also regulates the position of the plasmon resonance peak of
the silver nanocavity structure, rendering synchronous dual electromagnetic
and chemical regulation. Additionally, the method enables the trace
detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
A detailed theoretical analysis is performed based on the experimental
results and finite-element calculations, paving the way for the fabrication
of high-efficient E-SERS substrates.