Electromagnetic field emitted by core–shell semiconductor nanowires driven by an alternating current

The exploration of the plasmonic field enhancement of nanoprobes consisting of gold and magnetic core@gold shell nanoparticles has found increasing application for the development of surface-enhanced Raman spectroscopy (SERS)-based biosensors. The understanding of factors controlling the electromagnetic field enhancement, as a result of the plasmonic field enhancement of the nanoprobes in SERS biosensing applications, is critical for the design and preparation of the optimal nanoprobes. This report describes findings from theoretical calculations of the electromagnetic field intensity of dimer models of gold and magnetic core@gold shell nanoparticles in immunoassay SERS detection of biomarkers. The electromagnetic field intensities for a series of dimeric nanoprobes with antibody–antigen–antibody binding defined interparticle distances were examined in terms of nanoparticle sizes, core–shell sizes, and interparticle spacing. The results reveal that the electromagnetic field enhancement not only depended on the nanoparticle size and the relative core size and shell thicknesses of the magnetic core@shell nanoparticles but also strongly on the interparticle spacing. Some of the dependencies are also compared with experimental data from SERS detection of selected cancer biomarkers, showing good agreement. The findings have implications for the design and optimization of functional nanoprobes for SERS-based biosensors.

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Band structure of core-shell semiconductor nanowires

Physical Review B ◽

10.1103/physrevb.78.115319 ◽

2008 ◽

Vol 78 (11) ◽

Cited By ~ 81

Author(s):

M.-E. Pistol ◽

C. E. Pryor

Keyword(s):

Band Structure ◽

Semiconductor Nanowires ◽

Core Shell

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Defect control and Si/Ge core-shell heterojunction formation on silicon nanowire surfaces formed using the top-down method

Nanotechnology ◽

10.1088/1361-6528/ac3fe4 ◽

2021 ◽

Author(s):

Naoki Fukata ◽

Wipakorn Jevasuwan ◽

Yonglie Sun ◽

Yoshimasa Sugimoto

Keyword(s):

Surface Defects ◽

Silicon Nanowire ◽

Impurity Scattering ◽

Surface Damage ◽

Semiconductor Nanowires ◽

Core Shell ◽

Shell Formation ◽

Top Down ◽

Defect Control ◽

Impurity Doping

Abstract Control of surface defects and impurity doping are important keys to realizing devices that use semiconductor nanowires (NWs). As a structure capable of suppressing impurity scattering, p-Si/i (intrinsic)-Ge core-shell NWs with radial heterojunctions inside the NWs were formed. When forming NWs using a top-down method, the positions of the NWs can be controlled, but their surface is damaged. When heat treatment for repairing surface damage is performed, the surface roughness of the NWs closely depends on the kind of atmospheric gas. Oxidation and chemical etching prior to shell formation removes the surface damaged layer on p-SiNWs and simultaneously achieves a reduction in the diameter of the NWs. Finally, hole gas accumulation, which is important for suppressing impurity scattering, can be observed in the i-Ge layers of p-Si/i-Ge core-shell NWs.

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