Fabrication of single-nanometer metallic gaps via spontaneous nanoscale dewetting

Zeng, Pei; Shu, Zhiwen; Zhang, Shi; Liang, Huikang; Zhou, Yuting; Ba, Dedong; Feng, Zhanzu; Zheng, Mengjie; Wu, Jiangning; Chen, Yiqin; Duan, Huigao

doi:10.1088/1361-6528/abe576

Cited by 6 publications

(4 citation statements)

References 38 publications

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“…For detecting crystal violet molecules, the crystal violet standard solution was prepared by dissolving the crystal violet powder into deionized water. All samples were incubated in the crystal violet solution dissolved in DI water for 24 h and then dried with nitrogen gas to obtain an average single molecular layer [27,28]. After that, the samples were subjected to SERS measurement.…”

Section: Sers Measurementmentioning

confidence: 99%

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Wafer-Level Highly Dense Metallic Nanopillar-Enabled High-Performance SERS Substrates for Molecular Detection

et al. 2023

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Seeking sensitive, large-scale, and low-cost substrates is highly important for practical applications of surface-enhanced Raman scattering (SERS) technology. Noble metallic plasmonic nanostructures with dense hot spots are considered an effective construction to enable sensitive, uniform, and stable SERS performance and thus have attracted wide attention in recent years. In this work, we reported a simple fabrication method to achieve wafer-scale ultradense tilted and staggered plasmonic metallic nanopillars filled with numerous nanogaps (hot spots). By adjusting the etching time of the PMMA (polymethyl methacrylate) layer, the optimal SERS substrate with the densest metallic nanopillars was obtained, which possessed a detection limit down to 10−13 M by using crystal violet as the detected molecules and exhibited excellent reproducibility and long-term stability. Furthermore, the proposed fabrication approach was further used to prepare flexible substrates; for example, a SERS flexible substrate was proven to be an ideal platform for analyzing low-concentration pesticide residues on curved fruit surfaces with significantly enhanced sensitivity. This type of SERS substrate possesses potential in real-life applications as low-cost and high-performance sensors.

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Section: Sers Measurementmentioning

confidence: 99%

“…The simulations were conducted by the three-dimensional FDTD solutions (Lumerical Solutions, Version 8.15.736) to obtain the electric field distribution profile [17,27]. The simplified calculated model based on Figure 2d was used for a simple qualitative analysis of electromagnetic field enhancement.…”

Section: Fdtd Simulationmentioning

confidence: 99%

Wafer-Level Highly Dense Metallic Nanopillar-Enabled High-Performance SERS Substrates for Molecular Detection

et al. 2023

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“…Electron beam lithography (EBL) is one of the most crucial technologies in fabricating tiny nanogaps because of its excellent flexibility and high resolution [16][17][18]. While the proximity effect resulted from the electron scattering in photoresist and substrate became the Achilles' heel, which dramatically inhibits the fabricating accuracy, stability, uniformity and reliability of EBL in the fabrication of sub-10 nm gaps [19,20].…”

Section: Introductionmentioning

confidence: 99%

Sub-10 nm metal nanogaps with high SERS performance via a novel conformal coating process

Wang¹,

Huang²,

He³

et al. 2023

J. Micromech. Microeng.

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Metallic nanogaps enables inducing the strong coupling between neighboring metal structures, resulting in a great field enhancement in the gap. Therefore, it is crucial fundamental building blocks for nanoelectronics and nanophotonics. Moreover, the electromagnetic field enhancement of the tiny gaps increases rapidly with the decrease of gaps size. Naturally, enables better device performance with higher field enhancements. However, as the size of nanogaps reduced to the sub-10-nm scale, the fabrication of metallic nanogaps faced with great challenges, including the decrease in uniformity, repeatability and stability of the fabricating process due to various manufacturing and physical constraints. Thus, how to further reduce the size of metal nanogaps for higher device performance has become a key issue in this field. In this work, we propose and demonstrate a novel approach to fabricate sub-10-nm metal nanogaps by coating a conformal ultrathin oxide film via atomic-layer deposition. The method can fabricate sub-10 nm gap in dense metal-nanostructure arrays with high stability, reliability and uniformity, which provides a reliable technical for the fabrication and application of high-performed metallic nanogap structures and devices.

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“…A particularly interesting phenomenon of electromagnetic enhancement is related to the so-called 'nanogap' effect, where greatly enhanced Raman signals have been observed [7][8][9]. Metallic dimers with nanogaps are a kind of straightforward and serviceable constructions to produce greatly enhanced Raman signals due to that the ultra-small nanogaps between two neighboring metallic nanostructures can generate strong electric field enhancement [10][11][12][13][14][15]. Therefore, the fabrication of metallic nanogaps is of great importance in the SERS community.…”

Section: Introductionmentioning

confidence: 99%

Suspended 3D metallic dimers with sub-10 nm gap for high-sensitive SERS detection

Zeng¹,

Zhou²,

Shu³

et al. 2022

Nanotechnology

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The suspended metallic nanostructures with tiny gaps have certain advantages in surface-enhanced Raman scattering (SERS) due to the coaction of the tiny metallic nanogaps and the substrate-decoupled electromagnetism resonant modes. In this study, we used the lithographic HSQ/PMMA electron-beam bilayer resist exposure combined with a deposition-induced nanogap-narrowing process to define elevated suspended metallic nanodimers with tiny gaps for surface-enhanced Raman spectroscopy detection. By varying the deposited metal thickness, the metallic dimers with sub-10 nm gaps can be reliably obtained. These dimers with tunable nanogaps successfully served as excellent SERS substrates, exhibiting remarkable high-sensitivity detection ability for crystal violet molecules. Systematic experiments and simulations were conducted to explain the origin of the improved SERS performance. The results showed that the 3D elevated suspended metallic dimers could achieve a higher SERS enhancement factor than the metallic dimers on HSQ pillars and a common Si substrate, demonstrating that this kind of suspended metallic dimer is a promising route for highly sensitive SERS detection and other plasmonic applications.

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Fabrication of single-nanometer metallic gaps via spontaneous nanoscale dewetting

Cited by 6 publications

References 38 publications

Wafer-Level Highly Dense Metallic Nanopillar-Enabled High-Performance SERS Substrates for Molecular Detection

Wafer-Level Highly Dense Metallic Nanopillar-Enabled High-Performance SERS Substrates for Molecular Detection

Sub-10 nm metal nanogaps with high SERS performance via a novel conformal coating process

Suspended 3D metallic dimers with sub-10 nm gap for high-sensitive SERS detection

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