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Kolasinski KW. Metal-Assisted Catalytic Etching (MACE) for Nanofabrication of Semiconductor Powders. MICROMACHINES 2021; 12:776. [PMID: 34209231 PMCID: PMC8304928 DOI: 10.3390/mi12070776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 12/31/2022]
Abstract
Electroless etching of semiconductors has been elevated to an advanced micromachining process by the addition of a structured metal catalyst. Patterning of the catalyst by lithographic techniques facilitated the patterning of crystalline and polycrystalline wafer substrates. Galvanic deposition of metals on semiconductors has a natural tendency to produce nanoparticles rather than flat uniform films. This characteristic makes possible the etching of wafers and particles with arbitrary shape and size. While it has been widely recognized that spontaneous deposition of metal nanoparticles can be used in connection with etching to porosify wafers, it is also possible to produced nanostructured powders. Metal-assisted catalytic etching (MACE) can be controlled to produce (1) etch track pores with shapes and sizes closely related to the shape and size of the metal nanoparticle, (2) hierarchically porosified substrates exhibiting combinations of large etch track pores and mesopores, and (3) nanowires with either solid or mesoporous cores. This review discussed the mechanisms of porosification, processing advances, and the properties of the etch product with special emphasis on the etching of silicon powders.
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Affiliation(s)
- Kurt W Kolasinski
- Department of Chemistry, West Chester University, West Chester, PA 19383, USA
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2
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Rezvani SJ, Favre L, Giuli G, Wubulikasimu Y, Berbezier I, Marcelli A, Boarino L, Pinto N. Spontaneous shape transition of Mn x Ge 1- x islands to long nanowires. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:366-374. [PMID: 33981531 PMCID: PMC8093550 DOI: 10.3762/bjnano.12.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
We report experimental evidence for a spontaneous shape transition, from regular islands to elongated nanowires, upon high-temperature annealing of a thin Mn wetting layer evaporated on Ge(111). We demonstrate that 4.5 monolayers is the critical thickness of the Mn layer, governing the shape transition to wires. A small change around this value modulates the geometry of the nanostructures. The Mn-Ge alloy nanowires are single-crystalline structures with homogeneous composition and uniform width along their length. The shape evolution towards nanowires occurs for islands with a mean size of ≃170 nm. The wires, up to ≃1.1 μm long, asymptotically tend to ≃80 nm of width. We found that tuning the annealing process allows one to extend the wire length up to ≃1.5 μm with a minor rise of the lateral size to ≃100 nm. The elongation process of the nanostructures is in agreement with a strain-driven shape transition mechanism proposed in the literature for other heteroepitaxial systems. Our study gives experimental evidence for the spontaneous formation of spatially uniform and compositionally homogeneous Mn-rich GeMn nanowires on Ge(111). The reliable and simple synthesis approach allows one to exploit the room-temperature ferromagnetic properties of the Mn-Ge alloy to design and fabricate novel nanodevices.
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Affiliation(s)
- S Javad Rezvani
- INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 54, Frascati, Italy
- Advanced Materials Metrology and Life Science Division, INRiM (Istituto Nazionale di Ricerca Metrologica), Strada delle Cacce 91, Torino, Italy
| | - Luc Favre
- IM2NP, CNRS, Aix-Marseille Université, Marseille (AMU), France
| | - Gabriele Giuli
- School of Science and Technology, Geology division, University of Camerino, Camerino, Italy
| | - Yiming Wubulikasimu
- School of Science and Technology, Geology division, University of Camerino, Camerino, Italy
| | | | - Augusto Marcelli
- INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 54, Frascati, Italy
- CNR - Istituto Struttura della Materia and Elettra-Sincrotrone Trieste, Basovizza Area Science Park, 34149 Trieste, Italy
- RICMASS - Rome International Center for Materials Science – Superstripes, Via dei Sabelli 119A, 00185 Roma, Italy
| | - Luca Boarino
- Advanced Materials Metrology and Life Science Division, INRiM (Istituto Nazionale di Ricerca Metrologica), Strada delle Cacce 91, Torino, Italy
| | - Nicola Pinto
- Advanced Materials Metrology and Life Science Division, INRiM (Istituto Nazionale di Ricerca Metrologica), Strada delle Cacce 91, Torino, Italy
- School of Science and Technology, Physics division, University of Camerino, Camerino, Italy
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3
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Mazuritskiy MI, Lerer AM, Marcelli A, Dabagov SB, Coreno M, D'Elia A, Rezvani SJ. Wave propagation and focusing of soft X-rays by spherical bent microchannel plates. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:383-391. [PMID: 33650549 DOI: 10.1107/s1600577520016458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
Synchrotron radiation sources have been used to study the focusing properties and angular distribution of X-ray radiation at the exit of spherically bent microchannel plates (MCPs). In this contribution it is shown how soft X-ray radiation at energies up to 1.5 keV can be focused by spherically bent MCPs with curvature radii R of 30 mm and 50 mm. For these devices, a focus spot is detectable at a distance between the detector and the MCP of less than R/2, with a maximum focusing efficiency up to 23% of the flux illuminating the MCP. The soft X-ray radiation collected at the exit of microchannels of spherically bent MCPs are analyzed in the framework of a wave approximation. A theoretical model for the wave propagation of radiation through MCPs has been successfully introduced to explain the experimental results. Experimental data and simulations of propagating radiation represent a clear confirmation of the wave channeling phenomenon for the radiation in spherically bent MCPs.
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Affiliation(s)
- M I Mazuritskiy
- Physics Department, Southern Federal University, 344090 Rostov-on-Don, Russian Federation
| | - A M Lerer
- Physics Department, Southern Federal University, 344090 Rostov-on-Don, Russian Federation
| | - A Marcelli
- INFN - Laboratori Nazionali di Frascati, via Enrico Fermi 54, 00044 Frascati, Italy
| | - S B Dabagov
- INFN - Laboratori Nazionali di Frascati, via Enrico Fermi 54, 00044 Frascati, Italy
| | - M Coreno
- Istituto Struttura della Materia, CNR, Via del Fosso del Cavaliere 100, 00133 Rome, Italy
| | - A D'Elia
- IOM-CNR, Laboratorio Nazionale TASC, Basovizza SS-14, km 163.5, 34012 Trieste, Italy
| | - S J Rezvani
- INFN - Laboratori Nazionali di Frascati, via Enrico Fermi 54, 00044 Frascati, Italy
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Potassium-Doped Para-Terphenyl: Structure, Electrical Transport Properties and Possible Signatures of a Superconducting Transition. CONDENSED MATTER 2020. [DOI: 10.3390/condmat5040078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Preliminary evidence for the occurrence of high-TC superconductivity in alkali-doped organic materials, such as potassium-doped p-terphenyl (KPT), were recently obtained by magnetic susceptibility measurements and by the opening of a large superconducting gap as measured by ARPES and STM techniques. In this work, KPT samples have been synthesized by a chemical method and characterized by low-temperature Raman scattering and resistivity measurements. Here, we report the occurrence of a resistivity drop of more than 4 orders of magnitude at low temperatures in KPT samples in the form of compressed powder. This fact was interpreted as a possible sign of a broad superconducting transition taking place below 90 K in granular KPT. The granular nature of the KPT system appears to be also related to the 20 K broadening of the resistivity drop around the critical temperature.
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5
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Broadband optical ultrafast reflectivity of Si, Ge and GaAs. Sci Rep 2020; 10:17363. [PMID: 33060665 PMCID: PMC7567120 DOI: 10.1038/s41598-020-74068-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/21/2020] [Indexed: 11/09/2022] Open
Abstract
AbstractUltrafast optical reflectivity measurements of silicon, germanium, and gallium arsenide have been carried out using an advanced set-up providing intense subpicosecond pulses (35 fs FWHM, $$\lambda $$
λ
= 400 nm) as a pump and broadband 340–780 nm ultrafast pulses as a white supercontinuum probe. Measurements have been performed for selected pump fluence conditions below the damage thresholds, that were carefully characterized. The obtained fluence damage thresholds are 30, 20.8, 9.6 mJ/$$\hbox {cm}^2$$
cm
2
for Si, Ge and GaAs respectively. Ultrafast reflectivity patterns show clear differences in the Si, Ge, and GaAs trends both for the wavelength and time dependences. Important changes were observed near the wavelength regions corresponding to the $$E_1$$
E
1
, $$E_1+\Delta $$
E
1
+
Δ
singularities in the joint density of states, so related to the peculiar band structure of the three systems. For Ge, ultrafast reflectivity spectra were also collected at low temperature (down to 80 K) showing a shift of the characteristic doublet peak around 2.23 eV and a reduction of the recovery times.
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Detection of Spin Polarized Band in VO2/TiO2(001) Strained Films via Orbital Selective Constant Initial State Spectroscopy. CONDENSED MATTER 2020. [DOI: 10.3390/condmat5040072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The VO2 is a 3d1 electron system that undergoes a reversible metal–insulator transition (MIT) triggered by temperature and characterized by an interplay between orbital, charge and lattice degrees of freedom. The characterization of the MIT features are therefore extremely challenging and powerful investigation tools are required. In this work, we demonstrate how a combination of resonant photoemission and constant initial state (CIS) spectroscopy can be used as an orbital selective probe of the MIT studying three different VO2/TiO2(001) strained films. The CIS spectra of the V 3d and V 3p photo-electrons shows sensitivity to different orbital contribution and the presence of a spin polarized band close to the Fermi level.
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Engineering Porous Silicon Nanowires with Tuneable Electronic Properties. CONDENSED MATTER 2020. [DOI: 10.3390/condmat5040057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Structural and electronic properties of silicon nanowires with pre-designed structures are investigated. Wires with distinct structure were investigated via advanced spectroscopic techniques such as X-ray absorption spectroscopy and Raman scattering as well as transport measurements. We show that wire structures can be engineered with metal assisted etching fabrication process via the catalytic solution ratios as well as changing doping type and level. In this way unique well-defined electronic configurations and density of states are obtained in the synthesized wires leading to different charge carrier and phonon dynamics in addition to photoluminescence modulations. We demonstrate that the electronic properties of these structures depend by the final geometry of these systems as determined by the synthesis process. These wires are characterized by a large internal surface and a modulated DOS with a significantly high number of surface states within the band structure. The results improve the understanding of the different electronic structures of these semiconducting nanowires opening new possibilities of future advanced device designs.
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Rezvani SJ, Di Gioacchino D, Tofani S, D'Arco A, Ligi C, Lupi S, Gatti C, Cestelli Guidi M, Marcelli A. A cryogenic magneto-optical device for long wavelength radiation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:075103. [PMID: 32752830 DOI: 10.1063/5.0011348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
We present here a small-scale liquid helium immersion cryostat with an innovative optical setup suitable to work in long wavelength radiation ranges and under an applied magnetic field. The cryostat is a multi-stage device with several shielding in addition to several optical stages. The system has been designed with an external liquid nitrogen boiler to reduce liquid bubbling. The optical and mechanical properties of the optical elements were calculated and optimized for the designed configuration, while the optical layout has been simulated and optimized among different configurations based on the geometry of the device. The final design has been optimized for low-noise radiation measurements of proximity junction arrays under an applied magnetic field in the wavelength range λ = 250 μm-2500 μm.
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Affiliation(s)
- S J Rezvani
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
| | - D Di Gioacchino
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
| | - S Tofani
- Department of Information Engineering, Electronics and Telecommunications, "Sapienza" University of Rome, 00184 Rome, Italy
| | - A D'Arco
- Department of Physics, Sapienza University of Rome, 00185 Rome, Italy
| | - C Ligi
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
| | - S Lupi
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
| | - C Gatti
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
| | - M Cestelli Guidi
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
| | - A Marcelli
- INFN - Laboratori Nazionali di Frascati, Via Enrico 54, 00044 Frascati (RM), Italy
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Tamarov K, Swanson JD, Unger BA, Kolasinski KW, Ernst AT, Aindow M, Lehto VP, Riikonen J. Controlling the Nature of Etched Si Nanostructures: High- versus Low-Load Metal-Assisted Catalytic Etching (MACE) of Si Powders. ACS APPLIED MATERIALS & INTERFACES 2020; 12:4787-4796. [PMID: 31888334 DOI: 10.1021/acsami.9b20514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Metal-assisted catalytic etching (MACE) involving Ag deposited on Si particles has been reported as a facile method for the production of Si nanowires (Si NWs). We show that the structure of Si particles subjected to MACE changes dramatically in response to changing the loading of the Ag catalyst. The use of acetic acid as a surfactant and controlled injection of AgNO3(aq) enhanced Ag deposition. The use of acetic acid and controlled injection of H2O2 not only facilitated optimization of the etching step but also allowed us to identify a previously unobserved etching regime that we denote as low-load MACE (LL-MACE). Material produced by LL-MACE exhibits dramatically different yield and structural characteristics as compared to conventionally produced material. We demonstrate the production of Si NWs as well as mesoporous Si nanoparticles from an inexpensive metallurgical-grade Si powder. High loading of Ag (HL-MACE) generates parallel etch track pores created by the correlated motion of Ag nanoparticles. The uniform size distribution (predominantly 70-100 nm) of the Ag nanoparticles is generated dynamically during etching. The walls of these etch track pores are cleaved readily by ultrasonic agitation to form Si NWs. Low loading of Ag (LL-MACE) creates 10-50 nm Ag nanoparticles that etch in an uncorrelated (randomly directed) fashion to generate a bimodal distribution of mesoporosity peaking at ∼4 and 13-21 nm. The use of a syringe pump to deliver the oxidant (H2O2) and Ag+ is essential for increased product uniformity and yield. Different process temperatures and grades of Si produced significantly different pore size distributions. These results facilitate the production of Si NWs and mesoporous nanoparticles with high yield, low cost, and controlled properties that are suitable for applications in, e.g., lithium-ion batteries, drug delivery, as well as biomedical imaging and contrast enhancement.
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Affiliation(s)
- Konstantin Tamarov
- Department of Applied Physics , University of Eastern Finland , Kuopio FI-70211 , Finland
| | - Joseph D Swanson
- Department of Chemistry , West Chester University , West Chester , Pennsylvania 19383 , United States
| | - Bret A Unger
- Department of Chemistry , West Chester University , West Chester , Pennsylvania 19383 , United States
| | - Kurt W Kolasinski
- Department of Chemistry , West Chester University , West Chester , Pennsylvania 19383 , United States
| | - Alexis T Ernst
- Department of Materials Science and Engineering, Institute of Materials Science , University of Connecticut , Storrs , Connecticut 06269 , United States
| | - Mark Aindow
- Department of Materials Science and Engineering, Institute of Materials Science , University of Connecticut , Storrs , Connecticut 06269 , United States
| | - Vesa-Pekka Lehto
- Department of Applied Physics , University of Eastern Finland , Kuopio FI-70211 , Finland
| | - Joakim Riikonen
- Department of Applied Physics , University of Eastern Finland , Kuopio FI-70211 , Finland
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Kolasinski KW, Unger BA, Ernst AT, Aindow M. Crystallographically Determined Etching and Its Relevance to the Metal-Assisted Catalytic Etching (MACE) of Silicon Powders. Front Chem 2019; 6:651. [PMID: 30701171 PMCID: PMC6343677 DOI: 10.3389/fchem.2018.00651] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 12/13/2018] [Indexed: 02/04/2023] Open
Abstract
Metal-assisted catalytic etching (MACE) using Ag nanoparticles as catalysts and H2O2 as oxidant has been performed on single-crystal Si wafers, single-crystal electronics grade Si powders, and polycrystalline metallurgical grade Si powders. The temperature dependence of the etch kinetics has been measured over the range 5-37°C. Etching is found to proceed preferentially in a 〈001〉 direction with an activation energy of ~0.4 eV on substrates with (001), (110), and (111) orientations. A quantitative model to explain the preference for etching in the 〈001〉 direction is developed and found to be consistent with the measured activation energies. Etching of metallurgical grade powders produces particles, the surfaces of which are covered primarily with porous silicon (por-Si) in the form of interconnected ridges. Silicon nanowires (SiNW) and bundles of SiNW can be harvested from these porous particles by ultrasonic agitation. Analysis of the forces acting between the metal nanoparticle catalyst and the Si particle demonstrates that strongly attractive electrostatic and van der Waals interactions ensure that the metal nanoparticles remain in intimate contact with the Si particles throughout the etch process. These attractive forces draw the catalyst toward the interior of the particle and explain why the powder particles are etched equivalently on all the exposed faces.
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Affiliation(s)
- Kurt W Kolasinski
- Department of Chemistry, West Chester University, West Chester, PA, United States
| | - Bret A Unger
- Department of Chemistry, West Chester University, West Chester, PA, United States
| | - Alexis T Ernst
- Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT, United States
| | - Mark Aindow
- Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT, United States
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Rezvani SJ, Pinto N, Boarino L. Rapid formation of single crystalline Ge nanowires by anodic metal assisted etching. CrystEngComm 2016. [DOI: 10.1039/c6ce01598k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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