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Jo JS, Lee J, Choi C, Jang JW. Tip-based Lithography with a Sacrificial Layer. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309484. [PMID: 38287738 DOI: 10.1002/smll.202309484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/07/2023] [Indexed: 01/31/2024]
Abstract
The fabrication of a highly controlled gold (Au) nanohole (NH) array via tip-based lithography is improved by incorporating a sacrificial layer-a tip-crash buffer layer. This inclusion mitigates scratches during the nano-indentation process by employing a 300 nm thick poly(methyl methacrylate) layer as a sacrificial layer on top of the Au film. Such a precaution ensures minimal scratches on the Au film, facilitating the creation of sub-50 nm Au NHs with a 15 nm gap between the Au NHs. The precision of this method exceeds that of fabricating Au NHs without a sacrificial layer. Demonstrating its versatility, this Au NH array is utilized in two distinct applications: as a dry etching mask to form a molybdenum disulfide hole array and as a catalyst in metal-assisted chemical etching, resulting in conical-shaped silicon nanostructures. Additionally, a significant electric field is generated when Au nanoparticles (NPs) are placed within the Au NHs. This effect arises from coupling electromagnetic waves, concentrated by the Au NHs and amplified by the Au NPs. A notable result of this configuration is the enhancement factor of surface-enhanced Raman scattering, which is an order of magnitude greater than that observed with just Au NHs and Au NPs alone.
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Affiliation(s)
- Jeong-Sik Jo
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea
| | - Jinho Lee
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea
| | - Chiwon Choi
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea
| | - Jae-Won Jang
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea
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Gorshkov VN, Stretovych MO, Semeniuk VF, Kruglenko MP, Semeniuk NI, Styopkin VI, Gabovich AM, Boiger GK. Hierarchical Structuring of Black Silicon Wafers by Ion-Flow-Stimulated Roughening Transition: Fundamentals and Applications for Photovoltaics. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2715. [PMID: 37836356 PMCID: PMC10574651 DOI: 10.3390/nano13192715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/27/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023]
Abstract
Ion-flow-stimulated roughening transition is a phenomenon that may prove useful in the hierarchical structuring of nanostructures. In this work, we have investigated theoretically and experimentally the surface texturing of single-crystal and multi-crystalline silicon wafers irradiated using ion-beam flows. In contrast to previous studies, ions had relatively low energies, whereas flow densities were high enough to induce a quasi-liquid state in the upper silicon layers. The resulting surface modifications reduced the wafer light reflectance to values characteristic of black silicon, widely used in solar energetics. Features of nanostructures on different faces of silicon single crystals were studied numerically based on the mesoscopic Monte Carlo model. We established that the formation of nano-pyramids, ridges, and twisting dune-like structures is due to the stimulated roughening transition effect. The aforementioned variety of modified surface morphologies arises due to the fact that the effects of stimulated surface diffusion of atoms and re-deposition of free atoms on the wafer surface from the near-surface region are manifested to different degrees on different Si faces. It is these two factors that determine the selection of the allowable "trajectories" (evolution paths) of the thermodynamic system along which its Helmholtz free energy, F, decreases, concomitant with an increase in the surface area of the wafer and the corresponding changes in its internal energy, U (dU>0), and entropy, S (dS>0), so that dF=dU - TdS<0, where T is the absolute temperature. The basic theoretical concepts developed were confirmed in experimental studies, the results of which showed that our method could produce, abundantly, black silicon wafers in an environmentally friendly manner compared to traditional chemical etching.
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Affiliation(s)
- Vyacheslav N. Gorshkov
- Igor Sikorsky Kyiv Polytechnic Institute, National Technical University of Ukraine, Prospect Beresteiskyi, 37, 03056 Kyiv, Ukraine;
- G.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences of Ukraine, 36 Academician Vernadsky Boulevard, 03142 Kyiv, Ukraine
- Department of Mechanical and Aerospace Engineering, University of Liverpool, Liverpool L69 3GH, UK
| | - Mykola O. Stretovych
- Igor Sikorsky Kyiv Polytechnic Institute, National Technical University of Ukraine, Prospect Beresteiskyi, 37, 03056 Kyiv, Ukraine;
| | - Valerii F. Semeniuk
- Institute of Physics of the Ukrainian National Academy of Sciences, Nauka Avenue, 46, 03028 Kyiv, Ukraine; (V.F.S.); (M.P.K.); (V.I.S.); (A.M.G.)
- GreSem Innovation LLC, Vyzvolyteliv Avenue, 13, 02660 Kyiv, Ukraine;
| | - Mikhail P. Kruglenko
- Institute of Physics of the Ukrainian National Academy of Sciences, Nauka Avenue, 46, 03028 Kyiv, Ukraine; (V.F.S.); (M.P.K.); (V.I.S.); (A.M.G.)
- GreSem Innovation LLC, Vyzvolyteliv Avenue, 13, 02660 Kyiv, Ukraine;
| | | | - Victor I. Styopkin
- Institute of Physics of the Ukrainian National Academy of Sciences, Nauka Avenue, 46, 03028 Kyiv, Ukraine; (V.F.S.); (M.P.K.); (V.I.S.); (A.M.G.)
| | - Alexander M. Gabovich
- Institute of Physics of the Ukrainian National Academy of Sciences, Nauka Avenue, 46, 03028 Kyiv, Ukraine; (V.F.S.); (M.P.K.); (V.I.S.); (A.M.G.)
| | - Gernot K. Boiger
- ICP Institute of Computational Physics, ZHAW Zürich University of Applied Sciences, Wildbachstrasse 21, CH-8401 Winterthur, Switzerland
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Moram SSB, Byram C, Soma VR. Femtosecond laser patterned silicon embedded with gold nanostars as a hybrid SERS substrate for pesticide detection. RSC Adv 2023; 13:2620-2630. [PMID: 36741174 PMCID: PMC9844677 DOI: 10.1039/d2ra07859g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/10/2023] [Indexed: 01/19/2023] Open
Abstract
We have developed simple and cost-effective surface-enhanced Raman scattering (SERS) substrates for the trace detection of pesticide (thiram and thiabendazole) and dye (methylene blue and Nile blue) molecules. Surface patterns (micro/nanostructures) on silicon (Si) substrates were fabricated using the technique of femtosecond (fs) laser ablation in ambient air. Different surface patterns were achieved by tuning the number of laser pulses per unit area (4200, 8400, 42 000, and 84 000 pulses per mm2) on Si. Subsequently, chemically synthesized gold (Au) nanostars were embedded in these laser-patterned areas of Si to achieve a plasmonic active hybrid SERS substrate. Further, the SERS performance of the as-prepared Au nanostar embedded Si substrates were tested with different probe molecules. The as-prepared substrates allowed us to detect a minimum concentration of 0.1 ppm in the case of thiram, 1 ppm in the case of thiabendazole (TBZ), 1.6 ppb in the case of methylene blue (MB), and 1.8 ppb in case of Nile blue (NB). All these were achieved using a simple, field-deployable, portable Raman spectrometer. Additionally, the optimized SERS substrate demonstrated ∼21 times higher SERS enhancement than the Au nanostar embedded plain Si substrate. Furthermore, the optimized SERS platform was utilized to detect a mixture of dyes (MB + NB) and pesticides (thiram + TBZ). The possible reasons for the observed additional enhancement are elucidated.
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Affiliation(s)
- Sree Satya Bharati Moram
- Advanced Centre for Research in High Energy Materials (ACRHEM), DRDO Industry Academia–Centre of Excellence (DIA-COE), University of HyderabadProf. C. R. Rao RoadHyderabad 500046TelanganaIndia
| | - Chandu Byram
- Department of Physics, College of Arts and Sciences, University of Dayton300 College ParkDaytonOhio 45469USA
| | - Venugopal Rao Soma
- Advanced Centre for Research in High Energy Materials (ACRHEM), DRDO Industry Academia–Centre of Excellence (DIA-COE), University of HyderabadProf. C. R. Rao RoadHyderabad 500046TelanganaIndia
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Flejszar M, Ślusarczyk K, Chmielarz P, Wolski K, Isse AA, Gennaro A, Wytrwal-Sarna M, Oszajca M. Working electrode geometry effect: A new concept for fabrication of patterned polymer brushes via SI-seATRP at ambient conditions. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Jeon GW, Lee SH, Jang JW. Opposite Raman Shift of Ring Stretching Dependent on the Coordinated Silver Volume in Surface-Enhanced Raman Spectroscopy of Polypyrrole. J Phys Chem Lett 2022; 13:1300-1306. [PMID: 35099975 DOI: 10.1021/acs.jpclett.1c04069] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) can sense some molecules in a nondestructive manner. Using SERS, we investigate the shifts in the Raman peaks of polypyrrole (PPy) with two different coordinated silver (Ag) structures, Ag nanoparticles (NPs) and Ag dendrite film. The SERS spectrum of PPy with Ag NPs presents a ring-stretching peak that is red-shifted compared to the ring-stretching peak in the Raman spectrum of PPy. In contrast, the spectrum of the PPy with the Ag dendrite film exhibits a blue-shifted ring stretching peak. The various coordinated Ag nanostructures result in opposite Raman shifts of the ring stretching peak; this phenomenon has been investigated and confirmed by density functional theory (DFT) calculations of the Raman shift of the pyrrole (Py) molecule with a Ag layer (SERS of PPy with Ag NPs) and that of a charge-transferred Py molecule (SERS of PPy with Ag dendrite films). This result demonstrates that DFT calculations can be an effective tool to scrutinize Raman shifts in SERS.
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Affiliation(s)
- Gi Wan Jeon
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea
| | - Seung-Hoon Lee
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Jae-Won Jang
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea
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