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Hwang JD, Liou YR, Chiou YJ. Studies of carrier transport mechanism in NiO/Ag/NiO transparent conducting electrode/ZnO metal-semiconductor-metal photodetectors. NANOTECHNOLOGY 2024; 35:335202. [PMID: 38763138 DOI: 10.1088/1361-6528/ad4d58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/19/2024] [Indexed: 05/21/2024]
Abstract
Oxide/metal/oxide multilayers as a transparent conducting electrode (TCE) have been developed to replace metals due to their high transparency and low sheet resistance. Nickel oxide (NiO) film with a high work function was used as an oxide to form NiO/Ag/NiO (NAN) TCE, therefore a high barrier height between NAN/zinc oxide (ZnO) interface. In the study, NAN TCE was deposited on ZnO surface to fabricate metal-semiconductor-metal (MSM) photodetectors (PDs) and study its carrier transport mechanism. The NAN TCE has a low sheet resistance of 6.5 Ω/sq. and transmittance more than 40% in a 300-1000 nm wavelength range. Such issues result in the figure-of-merit is higher (2.3 × 10-4Ω-1) than that (2.5 × 10-7Ω-1) of pure single NiO thin film. As compared to the conventional Au/ZnO MSM-PDs, the NAN/ZnO MSM-PDs demonstrates a lower leakage current as a result of Ni atoms diffusing into ZnO and passivating the defects. Due to the high work function of NiO, the NAN/ZnO interface exhibits a barrier height as high as 0.91 eV. The Au/ZnO MSM-PDs reveals only one carrier conduction of ohmic due to the electrons tunnel form Au into ZnO through the surface defects. In contrast, two distinct carrier transport mechanisms were observed in the NAN/ZnO MSM-PDs. At low-voltage forV⩽0.64 V, ohmic conduction dominates and the electrons inject from NAN to ZnO, trapped by the defect states of ZnO. At high-voltage for V⩾0.64 V, the trapped electrons acquire enough energy and emit from trap to conduction band, entering Poole-Frankel emission transport.
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Affiliation(s)
- J D Hwang
- Department of Electrophysics, National Chiayi University, No. 300 Syuefu Rd., Chiayi City 60004, Taiwan
| | - Y R Liou
- Department of Electrophysics, National Chiayi University, No. 300 Syuefu Rd., Chiayi City 60004, Taiwan
| | - Y J Chiou
- Department of Electrophysics, National Chiayi University, No. 300 Syuefu Rd., Chiayi City 60004, Taiwan
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Gawlik A, Brückner U, Schmidl G, Wagner V, Paa W, Plentz J. Amorphous Silicon Thin-Film Solar Cells on Fabrics as Large-Scale Detectors for Textile Personal Protective Equipment in Active Laser Safety. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4841. [PMID: 37445156 DOI: 10.3390/ma16134841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023]
Abstract
Laser safety is starting to play an increasingly important role, especially when the laser is used as a tool. Passive laser safety systems quickly reach their limits and, in some cases, provide inadequate protection. To counteract this, various active systems have been developed. Flexible and especially textile-protective materials pose a special challenge. The market still lacks personal protective equipment (PPE) for active laser safety. Covering these materials with solar cells as large-area optical detectors offers a promising possibility. In this work, an active laser protection fabric with amorphous silicon solar cells is presented as a large-scale sensor for continuous wave and pulsed lasers (down to ns). First, the fabric and the solar cells were examined separately for irradiation behavior and damage. Laser irradiation was performed at wavelengths of 245, 355, 532, and 808 nm. The solar cell sensors were then applied directly to the laser protection fabric. The damage and destruction behavior of the active laser protection system was investigated. The results show that the basic safety function of the solar cell is still preserved when the locally damaged or destroyed area is irradiated again. A simple automatic shutdown system was used to demonstrate active laser protection within 50 ms.
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Affiliation(s)
- Annett Gawlik
- Leibniz Institute of Photonic Technology (Leibniz IPHT), Department of Functional Interfaces, Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Uwe Brückner
- Leibniz Institute of Photonic Technology (Leibniz IPHT), Department of Functional Interfaces, Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Gabriele Schmidl
- Leibniz Institute of Photonic Technology (Leibniz IPHT), Department of Functional Interfaces, Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Volker Wagner
- Leibniz Institute of Photonic Technology (Leibniz IPHT), Department of Functional Interfaces, Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Wolfgang Paa
- Leibniz Institute of Photonic Technology (Leibniz IPHT), Department of Functional Interfaces, Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Jonathan Plentz
- Leibniz Institute of Photonic Technology (Leibniz IPHT), Department of Functional Interfaces, Albert-Einstein-Strasse 9, 07745 Jena, Germany
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3
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Cheng L, Tuersun P, Ma D, Wumaier D, Li Y. Inversion of the Complex Refractive Index of Au-Ag Alloy Nanospheres Based on the Contour Intersection Method. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16093291. [PMID: 37176173 PMCID: PMC10179709 DOI: 10.3390/ma16093291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023]
Abstract
The contour intersection method is a new method used to invert the complex refractive index of small particles. Research has yet to be reported on using this method to invert the complex refractive index of nanoparticles. This paper reports the feasibility and reliability of the contour intersection method in the inversion of the complex refractive index of nanoparticles using Au-Ag alloy nanospheres. The Mie theory and the size-dependent dielectric function are used to calculate the light scattering and absorption efficiency of Au-Ag alloy nanospheres corresponding to the complex refractive index. The complex refractive index of the particles is obtained by inversion with the contour intersection method. The backscattering efficiency constraint method is used to determine the unique solution when multiple valid solutions from the contour intersection method appear. The effects of the Au component percentage, particle size, and measurement errors on the inversion results are quantitatively analyzed. Finally, the inversion accuracy is compared and analyzed with the traditional iterative method. The results show that as long as the light scattering efficiency, light absorption efficiency, and backscattering efficiency of Au nanospheres can be measured, the accurate complex refractive index can also be calculated by inversion using the contour intersection method. The accuracy of the inversion results can be ensured when the measurement error is less than 5%. The results of inversion using the contour intersection method are better than those of the iterative methods under the same conditions. This study provides a simple and reliable inversion method for measuring the complex refractive index of Au-Ag alloy nanospheres.
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Affiliation(s)
- Long Cheng
- Xinjiang Key Laboratory for Luminescence Minerals and Optical Functional Materials, School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China
| | - Paerhatijiang Tuersun
- Xinjiang Key Laboratory for Luminescence Minerals and Optical Functional Materials, School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China
| | - Dengpan Ma
- Xinjiang Key Laboratory for Luminescence Minerals and Optical Functional Materials, School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China
| | - Dilishati Wumaier
- Xinjiang Key Laboratory for Luminescence Minerals and Optical Functional Materials, School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China
| | - Yixuan Li
- Xinjiang Key Laboratory for Luminescence Minerals and Optical Functional Materials, School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China
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Wei B, Li L, Shao L, Wang J. Crystalline-Amorphous Nanostructures: Microstructure, Property and Modelling. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2874. [PMID: 37049168 PMCID: PMC10095846 DOI: 10.3390/ma16072874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 06/19/2023]
Abstract
Crystalline metals generally exhibit good deformability but low strength and poor irradiation tolerance. Amorphous materials in general display poor deformability but high strength and good irradiation tolerance. Interestingly, refining characteristic size can enhance the flow strength of crystalline metals and the deformability of amorphous materials. Thus, crystalline-amorphous nanostructures can exhibit an enhanced strength and an improved plastic flow stability. In addition, high-density interfaces can trap radiation-induced defects and accommodate free volume fluctuation. In this article, we review crystalline-amorphous nanocomposites with characteristic microstructures including nanolaminates, core-shell microstructures, and crystalline/amorphous-based dual-phase nanocomposites. The focus is put on synthesis of characteristic microstructures, deformation behaviors, and multiscale materials modelling.
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Affiliation(s)
- Bingqiang Wei
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA;
| | - Lin Li
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA;
| | - Lin Shao
- Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843, USA;
| | - Jian Wang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA;
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Osseointegration Properties of Titanium Implants Treated by Nonthermal Atmospheric-Pressure Nitrogen Plasma. Int J Mol Sci 2022; 23:ijms232315420. [PMID: 36499747 PMCID: PMC9740438 DOI: 10.3390/ijms232315420] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/01/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Pure titanium is used in dental implants owing to its excellent biocompatibility and physical properties. However, the aging of the material during storage is detrimental to the long-term stability of the implant after implantation. Therefore, in this study, we attempted to improve the surface properties and circumvent the negative effects of material aging on titanium implants by using a portable handheld nonthermal plasma device capable of piezoelectric direct discharge to treat pure titanium discs with nitrogen gas. We evaluated the osteogenic properties of the treated samples by surface morphology and elemental analyses, as well as in vitro and in vivo experiments. The results showed that nonthermal atmospheric-pressure nitrogen plasma can improve the hydrophilicity of pure titanium without damaging its surface morphology while introducing nitrogen-containing functional groups, thereby promoting cell attachment, proliferation, and osseointegration to some extent. Therefore, nitrogen plasma treatment may be a promising method for the rapid surface treatment of titanium implants.
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Maria Jose L, Anna Thomas S, Aravind A, Ma YR, Anil Kadam S. Effect of Ni Doping on the Adsorption and Visible light Photocatalytic Activity of ZnO Hexagonal Nanorods. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.110208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kumar N, Poulose V, Laz YT, Chandra F, Abubakar S, Abdelhamid AS, Alzamly A, Saleh N. Temperature Control of Yellow Photoluminescence from SiO 2-Coated ZnO Nanocrystals. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3368. [PMID: 36234495 PMCID: PMC9565792 DOI: 10.3390/nano12193368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/23/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
In this study, we aimed to elucidate the effects of temperature on the photoluminescence from ZnO-SiO2 nanocomposite and to describe the preparation of SiO2-coated ZnO nanocrystals using a chemical precipitation method, as confirmed by Fourier transform infrared (FTIR) and powder X-ray diffraction analysis (XRD) techniques. Analyses using high-resolution transmission microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and electrophoretic light scattering (ELS) techniques showed that the new nanocomposite has an average size of 70 nm and 90% silica. Diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and photoluminescence-excitation (PLE) measurements at different temperatures revealed two emission bands at 385 and 590 nm when the nanomaterials were excited at 325 nm. The UV and yellow emission bands were attributed to the radiative recombination and surface defects. The variable-temperature, time-resolved photoluminescence (VT-TRPL) measurements in the presence of SiO2 revealed the increase in the exciton lifetime values and the interplay of the thermally induced nonradiative recombination transfer of the excited-state population of the yellow emission via deep centers (DC). The results pave the way for more applications in photocatalysis and biomedical technology.
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Affiliation(s)
- Narender Kumar
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Vijo Poulose
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Youssef Taiser Laz
- Academic Support Department, Abu Dhabi Polytechnic, Al Ain P.O. Box 15551, United Arab Emirate
| | - Falguni Chandra
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Salma Abubakar
- Science Division, New York University Abu Dhabi (NYUAD), Saadiyat Island P.O. Box 129188, United Arab Emirates
| | - Abdalla S. Abdelhamid
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Ahmed Alzamly
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Na’il Saleh
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
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8
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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, SWITZERLAND) 2022; 12:3209. [PMID: 36144997 PMCID: PMC9505617 DOI: 10.3390/nano12183209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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Abstract
Dental caries is a major lifestyle concern as dental components affect the face of an individual. The issue of tooth decay occurs in every age group throughout the globe. Researchers are probing incipient implements and techniques to develop filling agents for decayed teeth. Zinc oxide (ZnO) powder is utilized mostly as a filling agent. Nanotechnology enhanced the efficiency of compounds of metal oxides utilized for dental caries. The present study aims to investigate the properties of ZnO nanoparticles (NPs) synthesized chemically (using ZnCl2 and NaOH) as well as biologically (using aqueous leaf extract of Murraya paniculata). The XRD patterns confirm that ZnO NPs have a hexagonal crystalline structure with particle sizes of 47 nm and 55 nm for chemically and biologically synthesized NPs, respectively. The FE-SEM data confirm the nanorod and spherical/cubical shape morphologies for the chemically and biologically synthesized ZnO NPs, respectively. FTIR data show the peaks between 4000 and 450 cm−1 of the functional groups of –OH, C-O, –C-H-, and Zn-O bonds. The UV–Vis absorption study indicates a peak around 370 nm and a hump around 360 nm corresponding to the chemically and biologically synthesized ZnO NPs, respectively. An antibacterial bioassay was performed and compared with commercially available ZnO bulk powder against tooth decaying pathogens, viz., Streptococcus mutans, Staphylococcus aureus, E. coli, and Lactobacillus fermentum, and found that both ZnO NPs had results closer to those of the standard drug (rifampicin). Thus, the synthesized ZnO NPs may be utilized as nano-drugs for the application of tooth decaying filling agents. Even biologically synthesized ZnO NPs may be considered more environmentally friendly and less toxic to human health concerns.
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10
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Memristive Characteristics of the Single-Layer P-Type CuAlO 2 and N-Type ZnO Memristors. MATERIALS 2022; 15:ma15103637. [PMID: 35629662 PMCID: PMC9146962 DOI: 10.3390/ma15103637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/13/2022] [Accepted: 05/17/2022] [Indexed: 02/01/2023]
Abstract
Memristive behaviors are demonstrated in the single-layer oxide-based devices. The conduction states can be continually modulated with different pulses or voltage sweeps. Here, the p-CuAlO2- and n-ZnO-based memristors show the opposite bias polarity dependence with the help of tip electrode. It is well known that the conductivity of p-type and n-type semiconductor materials has the opposite oxygen concentration dependence. Thus, the memristive behaviors may attribute to the oxygen ion migration in the dielectric layers for the single-layer oxide based memristors. Further, based on the redox, the model of compressing dielectric layer thickness has been proposed to explain the memristive behavior.
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Acharya TR, Lamichhane P, Wahab R, Chaudhary DK, Shrestha B, Joshi LP, Kaushik NK, Choi EH. Study on the Synthesis of ZnO Nanoparticles Using Azadirachta indica Extracts for the Fabrication of a Gas Sensor. Molecules 2021; 26:molecules26247685. [PMID: 34946767 PMCID: PMC8703601 DOI: 10.3390/molecules26247685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022] Open
Abstract
This paper compared the effects of A. indica plant proteins over chemical methods in the morphology of zinc oxide nanoparticles (ZnO NPs) prepared by a co-precipitation method, and ethanol sensing performance of prepared thin films deposited over a fluorene-doped tin oxide (FTO) bind glass substrate using spray pyrolysis technique. The average crystallite sizes and diameters of the grain-sized cluster ZnO NPs were 25 and (701.79 ± 176.21) nm for an undoped sample and 20 and (489.99 ± 112.96) nm for A. india dye-doped sample. The fourier transform infrared spectroscopy (FTIR) analysis confirmed the formation of the Zn-O bond at 450 cm-1, and also showed the presence of plant proteins due to A. indica dye extracts. ZnO NPs films exhibited good response (up to 51 and 72% for without and with A. indica dye-doped extracts, respectively) toward ethanol vapors with quick response-recovery characteristics at a temperature of 250 °C for undoped and 225 °C for A. indica dye-doped ZnO thin films. The interaction of A. indica dye extracts helps to decrease the operating temperature and increased the response and recovery rates of the sensor, which may be due to an increase in the specific surface area, resulting in adsorption of more oxygen and hence high response results.
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Affiliation(s)
- Tirtha Raj Acharya
- Plasma Bioscience Research Center, Applied Plasma Medicine Center, Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Korea; (T.R.A.); (P.L.)
- Department of Physics, Saint Xavier’s College, Tribhuvan University, Maitighar, Kathmandu 44600, Nepal
| | - Pradeep Lamichhane
- Plasma Bioscience Research Center, Applied Plasma Medicine Center, Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Korea; (T.R.A.); (P.L.)
| | - Rizwan Wahab
- Chair for DNA Research, Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Dinesh Kumar Chaudhary
- Department of Physics, Amrit Campus, Tribhuvan University, Kathmandu 44600, Nepal; (D.K.C.); (L.P.J.)
| | - Bhanu Shrestha
- Department of Electronic Engineering, Kwangwoon University, Seoul 01897, Korea;
| | - Leela Pradhan Joshi
- Department of Physics, Amrit Campus, Tribhuvan University, Kathmandu 44600, Nepal; (D.K.C.); (L.P.J.)
| | - Nagendra Kumar Kaushik
- Plasma Bioscience Research Center, Applied Plasma Medicine Center, Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Korea; (T.R.A.); (P.L.)
- Correspondence: (N.K.K.); (E.H.C.)
| | - Eun Ha Choi
- Plasma Bioscience Research Center, Applied Plasma Medicine Center, Department of Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Korea; (T.R.A.); (P.L.)
- Correspondence: (N.K.K.); (E.H.C.)
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Houska J. Maximum Achievable N Content in Atom-by-Atom Growth of Amorphous Si-B-C-N Materials. MATERIALS (BASEL, SWITZERLAND) 2021; 14:5744. [PMID: 34640138 PMCID: PMC8510390 DOI: 10.3390/ma14195744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 11/16/2022]
Abstract
Amorphous Si-B-C-N alloys can combine exceptional oxidation resistance up to 1500 °C with high-temperature stability of superior functional properties. Because some of these characteristics require as high N content as possible, the maximum achievable N content in amorphous Si-B-C-N is examined by combining extensive ab initio molecular dynamics simulations with experimental data. The N content is limited by the formation of unbonded N2 molecules, which depends on the composition (most intensive in C rich materials, medium in B rich materials, least intensive in Si-rich materials) and on the density (increasing N2 formation with decreasing packing factor when the latter is below 0.28, at a higher slope of this increase at lower B content). The maximum content of N bonded in amorphous Si-B-C-N networks of lowest-energy densities is in the range from 34% to 57% (materials which can be grown without unbonded N2) or at most from 42% to 57% (at a cost of affecting materials characteristics by unbonded N2). The results are important for understanding the experimentally reported nitrogen contents, design of stable amorphous nitrides with optimized properties and pathways for their preparation, and identification of what is or is not possible to achieve in this field.
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Affiliation(s)
- Jiri Houska
- Department of Physics and NTIS-European Centre of Excellence, University of West Bohemia, Univerzitni 8, 30614 Plzen, Czech Republic
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13
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Lee S, Nam K, Kim JH, Hong GY, Kim SD. Effects of Seed-Layer N 2O Plasma Treatment on ZnO Nanorod Based Ultraviolet Photodetectors: Experimental Investigation with Two Different Device Structures. NANOMATERIALS 2021; 11:nano11082011. [PMID: 34443842 PMCID: PMC8398532 DOI: 10.3390/nano11082011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022]
Abstract
The crystalline quality of ZnO NR (nanorod) as a sensing material for visible blind ultraviolet PDs (photodetectors) critically depends on the SL (seed layer) material of properties, which is a key to high-quality nanocrystallite growth, more so than the synthesis method. In this study, we fabricated two different device structures of a gateless AlGaN/GaN HEMT (high electron mobility transistor) and a photoconductive PD structure with an IDE (interdigitated electrode) pattern implemented on a PET (polyethylene terephthalate) flexible substrate, and investigated the impact on device performance through the SL N2O plasma treatment. In case of HEMT-based PD, the highest current on-off ratio (~7) and spectral responsivity R (~1.5 × 105 A/W) were obtained from the treatment for 6 min, whereas the IDE pattern-based PD showed the best performance (on-off ratio = ~44, R = ~69 A/W) from the treatment for 3 min and above, during which a significant etch damage on PET substrates was produced. This improvement in device performance was due to the enhancement in NR crystalline quality as revealed by our X-ray diffraction, photoluminescence, and microanalysis.
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Abstract
The concept of “high entropy” was first proposed while exploring the unknown center of the metal alloy phase diagram, and then expanded to oxides. The colossal dielectric constant found on the bulk high-entropy oxides (HEOs) reveals the potential application of the high-entropy oxides in the dielectric aspects. Despite the fact that known HEO thin films have not been reported in the field of dielectric properties so far, with the high-entropy effects and theoretical guidance of high entropy, it is predictable that they will be discovered. Currently, researchers are verifying that appropriately increasing the oxygen content in the oxide, raising the temperature and raising the pressure during preparation have an obvious influence on thin films’ resistivity, which may be the guidance on obtaining an HEO film large dielectric constant. Finally, it could composite a metal–insulator–metal capacitor, and contribute to sensors and energy storage devices’ development; alternatively, it could be put into application in emerging thin-film transistor technologies, such as those based on amorphous metal oxide semiconductors, semiconducting carbon nanotubes, and organic semiconductors.
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Crapanzano R, Villa I, Mostoni S, D’Arienzo M, Di Credico B, Fasoli M, Scotti R, Vedda A. Morphology Related Defectiveness in ZnO Luminescence: From Bulk to Nano-Size. NANOMATERIALS 2020; 10:nano10101983. [PMID: 33036427 PMCID: PMC7601266 DOI: 10.3390/nano10101983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/30/2020] [Accepted: 10/03/2020] [Indexed: 12/04/2022]
Abstract
This study addresses the relationship between material morphology (size, growth parameters and interfaces) and optical emissions in ZnO through an experimental approach, including the effect of different material dimensions from bulk to nano-size, and different excitations, from optical sources to ionizing radiation. Silica supported ZnO nanoparticles and ligand capped ZnO nanoparticles are synthesized through a sol–gel process and hot injection method, respectively. Their optical properties are investigated by radioluminescence, steady-state and time-resolved photoluminescence, and compared to those of commercial micrometric powders and of a bulk single crystal. The Gaussian spectral reconstruction of all emission spectra highlights the occurrence of the same emission bands for all samples, comprising one ultraviolet excitonic peak and four visible defect-related components, whose relative intensities and time dynamics vary with the material parameters and the measurement conditions. The results demonstrate that a wide range of color outputs can be obtained by tuning synthesis conditions and size of pure ZnO nanoparticles, with favorable consequences for the engineering of optical devices based on this material.
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Affiliation(s)
- Roberta Crapanzano
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (R.C.); (M.F.); (A.V.)
| | - Irene Villa
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (R.C.); (M.F.); (A.V.)
- Correspondence: ; Tel.: +39-02-6448-5169
| | - Silvia Mostoni
- Department of Materials Science, INSTM, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (S.M.); (M.D.); (B.D.C.); (R.S.)
| | - Massimiliano D’Arienzo
- Department of Materials Science, INSTM, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (S.M.); (M.D.); (B.D.C.); (R.S.)
| | - Barbara Di Credico
- Department of Materials Science, INSTM, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (S.M.); (M.D.); (B.D.C.); (R.S.)
| | - Mauro Fasoli
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (R.C.); (M.F.); (A.V.)
| | - Roberto Scotti
- Department of Materials Science, INSTM, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (S.M.); (M.D.); (B.D.C.); (R.S.)
| | - Anna Vedda
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy; (R.C.); (M.F.); (A.V.)
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