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Ursaki V, Braniste T, Zalamai V, Rusu E, Ciobanu V, Morari V, Podgornii D, Ricci PC, Adelung R, Tiginyanu I. Aero-ZnS prepared by physical vapor transport on three-dimensional networks of sacrificial ZnO microtetrapods. Beilstein J Nanotechnol 2024; 15:490-499. [PMID: 38711580 PMCID: PMC11070954 DOI: 10.3762/bjnano.15.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 04/15/2024] [Indexed: 05/08/2024]
Abstract
Aeromaterials represent a class of increasingly attractive materials for various applications. Among them, aero-ZnS has been produced by hydride vapor phase epitaxy on sacrificial ZnO templates consisting of networks of microtetrapods and has been proposed for microfluidic applications. In this paper, a cost-effective technological approach is proposed for the fabrication of aero-ZnS by using physical vapor transport with Sn2S3 crystals and networks of ZnO microtetrapods as precursors. The morphology of the produced material is investigated by scanning electron microscopy (SEM), while its crystalline and optical qualities are assessed by X-ray diffraction (XRD) analysis and photoluminescence (PL) spectroscopy, respectively. We demonstrate possibilities for controlling the composition and the crystallographic phase content of the prepared aerogels by the duration of the technological procedure. A scheme of deep energy levels and electronic transitions in the ZnS skeleton of the aeromaterial was deduced from the PL analysis, suggesting that the produced aerogel is a potential candidate for photocatalytic and sensor applications.
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Affiliation(s)
- Veaceslav Ursaki
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau, Republic of Moldova
- Academy of Sciences of Moldova, Chisinau, Republic of Moldova
| | - Tudor Braniste
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau, Republic of Moldova
| | - Victor Zalamai
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau, Republic of Moldova
| | - Emil Rusu
- Institute of Electronic Engineering and Nanotechnology „D. Ghitu”, Technical University of Moldova, Chisinau, Republic of Moldova
| | - Vladimir Ciobanu
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau, Republic of Moldova
| | - Vadim Morari
- Institute of Electronic Engineering and Nanotechnology „D. Ghitu”, Technical University of Moldova, Chisinau, Republic of Moldova
| | - Daniel Podgornii
- Institute of Applied Physics, State University of Moldova, Chisinau, Republic of Moldova
| | | | - Rainer Adelung
- Department of Material Science, Kiel University, Kiel, Germany
| | - Ion Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau, Republic of Moldova
- Academy of Sciences of Moldova, Chisinau, Republic of Moldova
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Morari V, Ursaki VV, Rusu EV, Zalamai VV, Colpo P, Tiginyanu IM. Spin-Coating and Aerosol Spray Pyrolysis Processed Zn 1-xMg xO Films for UV Detector Applications. Nanomaterials (Basel) 2022; 12:3209. [PMID: 36144997 PMCID: PMC9505617 DOI: 10.3390/nano12183209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
A series of Zn1-xMgxO thin films with x ranging from 0 to 0.8 were prepared by spin coating and aerosol spray pyrolysis deposition on Si and quartz substrates. The morphology, composition, nano-crystalline structure, and optical and vibration properties of the prepared films were studied using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and optical and Raman scattering spectroscopy. The optimum conditions of the thermal treatment of samples prepared by spin coating were determined from the point of view of film crystallinity. The content of crystalline phases in films and values of the optical band gap of these phases were determined as a function of the chemical composition. We developed heterostructure photodetectors based on the prepared films and demonstrated their operation in the injection photodiode mode at forward biases. A device design based on two Zn1-xMgxO thin films with different x values was proposed for extending the operational forward bias range and improving its responsivity, detectivity, and selectivity to UV radiation.
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Affiliation(s)
- Vadim Morari
- D. Ghitu Institute of Electronic Engineering and Nanotechnologies, 2028 Chisinau, Moldova
| | - Veaceslav V. Ursaki
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova
- Academy of Sciences of Moldova, 2001 Chisinau, Moldova
| | - Emil V. Rusu
- D. Ghitu Institute of Electronic Engineering and Nanotechnologies, 2028 Chisinau, Moldova
| | - Victor V. Zalamai
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova
| | - Pascal Colpo
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Ion M. Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova
- Academy of Sciences of Moldova, 2001 Chisinau, Moldova
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Monaico EV, Morari V, Kutuzau M, Ursaki VV, Nielsch K, Tiginyanu IM. Magnetic Properties of GaAs/NiFe Coaxial Core-Shell Structures. Materials (Basel) 2022; 15:ma15186262. [PMID: 36143574 PMCID: PMC9502629 DOI: 10.3390/ma15186262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/31/2022] [Accepted: 09/06/2022] [Indexed: 06/12/2023]
Abstract
Uniform nanogranular NiFe layers with Ni contents of 65%, 80%, and 100% have been electroplated in the potentiostatic deposition mode on both planar substrates and arrays of nanowires prepared by the anodization of GaAs substrates. The fabricated planar and coaxial core-shell ferromagnetic structures have been investigated by means of scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). To determine the perspectives for applications, a comparative analysis of magnetic properties, in terms of the saturation and remanence moment, the squareness ratio, and the coercivity, was performed for structures with different Ni contents.
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Affiliation(s)
- Eduard V. Monaico
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova
| | - Vadim Morari
- Institute of Electronic Engineering and Nanotechnologies “D. Ghitu”, 2028 Chisinau, Moldova
| | - Maksim Kutuzau
- Institute for Metallic Materials (IMW), Leibniz Institute of Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Veaceslav V. Ursaki
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova
- Academy of Sciences of Moldova, 2001 Chisinau, Moldova
| | - Kornelius Nielsch
- Institute for Metallic Materials (IMW), Leibniz Institute of Solid State and Materials Research (IFW Dresden), Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Ion M. Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova
- Academy of Sciences of Moldova, 2001 Chisinau, Moldova
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Monaico EV, Morari V, Ursaki VV, Nielsch K, Tiginyanu IM. Core–Shell GaAs-Fe Nanowire Arrays: Fabrication Using Electrochemical Etching and Deposition and Study of Their Magnetic Properties. Nanomaterials 2022; 12:nano12091506. [PMID: 35564215 PMCID: PMC9104038 DOI: 10.3390/nano12091506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023]
Abstract
The preparation of GaAs nanowire templates with the cost-effective electrochemical etching of (001) and (111)B GaAs substrates in a 1 M HNO3 electrolyte is reported. The electrochemical etching resulted in the obtaining of GaAs nanowires with both perpendicular and parallel orientations with respect to the wafer surface. Core–shell GaAs-Fe nanowire arrays have been prepared by galvanostatic Fe deposition into these templates. The fabricated arrays have been investigated by means of scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The magnetic properties of the polycrystalline Fe nanotubes constituting the shells of the cylindrical structures, such as the saturation and remanence moment, squareness ratio, and coercivity, were analyzed in relation to previously reported data on ferromagnetic nanowires and nanotubes.
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Affiliation(s)
- Eduard V. Monaico
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova; (V.V.U.); (I.M.T.)
- Correspondence:
| | - Vadim Morari
- Institute of Electronic Engineering and Nanotechnologies “D. Ghitu”, 2028 Chisinau, Moldova;
| | - Veaceslav V. Ursaki
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova; (V.V.U.); (I.M.T.)
- Academy of Sciences of Moldova, 2001 Chisinau, Moldova
| | - Kornelius Nielsch
- Institute for Metallic Materials (IMW), Leibniz Institute of Solid State and Materials Research (IFW Dresden), Helmholtzstr. 20, 01069 Dresden, Germany;
| | - Ion M. Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, 2004 Chisinau, Moldova; (V.V.U.); (I.M.T.)
- Academy of Sciences of Moldova, 2001 Chisinau, Moldova
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Morari V, Pantazi A, Curmei N, Postolache V, Rusu EV, Enachescu M, Tiginyanu IM, Ursaki VV. Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films. Beilstein J Nanotechnol 2020; 11:899-910. [PMID: 32566440 PMCID: PMC7296199 DOI: 10.3762/bjnano.11.75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
A series of Zn1- x Mg x O thin films with the composition range x = 0.00-0.40 has been prepared by sol-gel spin coating on Si substrates with a post-deposition thermal treatment in the temperature range of 400-650 °C. The morphology of the films was investigated by scanning electron microscopy and atomic force microscopy while their light emission properties were studied by photoluminescence spectroscopy under excitation at 325 nm. It was found that annealing at 500 °C leads to the production of macroscopically homogeneous wurtzite phase films, while thermal treatment at higher or lower temperature results in the degradation of the morphology, or in the formation of ZnO particles embedded into the ZnMgO matrix, respectively. Local compositional fluctuations leading to the formation of deep band tails in the gap were deduced from photoluminescence spectra. A model for the band tail distribution in the bandgap is proposed as a function of the alloy composition. Thin films were also prepared by aerosol spray pyrolysis deposition using the same sol-gel precursors for the purpose of comparison. The prepared films were tested for photodetector applications.
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Affiliation(s)
- Vadim Morari
- D.Ghitu Institute of Electronic Engineering and Nanotechnologies, Chisinau MD-2028, Republic of Moldova
| | - Aida Pantazi
- Center for Surface Science and NanoTechnology, University Politehnica of Bucharest, 060042-Bucharest, Romania
| | - Nicolai Curmei
- Institute of Applied Physics, Chisinau MD-2028, Republic of Moldova
| | - Vitalie Postolache
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau MD-2004, Republic of Moldova
| | - Emil V Rusu
- D.Ghitu Institute of Electronic Engineering and Nanotechnologies, Chisinau MD-2028, Republic of Moldova
| | - Marius Enachescu
- Center for Surface Science and NanoTechnology, University Politehnica of Bucharest, 060042-Bucharest, Romania
| | - Ion M Tiginyanu
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau MD-2004, Republic of Moldova
| | - Veaceslav V Ursaki
- National Center for Materials Study and Testing, Technical University of Moldova, Chisinau MD-2004, Republic of Moldova
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