Nano-Structured Thin Films: Growth, Characteristics, and Application

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Synthesis, Interfaces and Nanostructures".

Deadline for manuscript submissions: closed (15 August 2024) | Viewed by 28406

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Graduate Institute of Electronic Engineering, Cheng-Shiu University, Kaohsiung, Taiwan
Interests: thin film technology; varistor memory; ferroelectric memory; semiconductor process technology; electronic ceramics
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Dear Colleagues,

Nanotechnology has gradually evolved in recent years, revealing different substances that are possessed under the nano-nanoparticles have many important applications and interesting materials. Nanotechnology is an applied science that studies the design, composition, properties, and applications of substances and devices at the nanoscale. Thin-film materials are thin metal substances or organic substances materials with thicknesses ranging from a single atom to a few millimeters. Electronic semiconductor devices and optical coatings are the main applications of thin film technology today. Thin film technology has a wide range of applications. Many researches have used different thin films for computer storage devices, pharmaceuticals, manufacturing thin-film batteries, dye-sensitized solar cells, and more. In addition, the ceramic thin films also have a wide range of applications. To the relatively high hardness of ceramic materials, such films were used to protect substrates from corrosion, oxidation, and wear. The present Special Issue of Nanomaterials aims to present nano-structured thin films, specifically their growth, characteristics, and application in various fields of technology and science. In the present Special Issue, we invited contributions from leading groups in the field with the aim of providing a balanced view of the current state-of-the-art in this discipline.

Prof. Dr. Kai-Huang Chen
Guest Editor

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Keywords

  • nano-structured
  • nanotechnology
  • nanoscale
  • thin films
  • growth
  • characteristics
  • science
  • coating
  • application

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Related Special Issue

Published Papers (17 papers)

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10 pages, 6226 KiB  
Article
Algorithm-Based Linearly Graded Compositions of GeSn on GaAs (001) via Molecular Beam Epitaxy
by Calbi Gunder, Mohammad Zamani-Alavijeh, Emmanuel Wangila, Fernando Maia de Oliveira, Aida Sheibani, Serhii Kryvyi, Paul C. Attwood, Yuriy I. Mazur, Shui-Qing Yu and Gregory J. Salamo
Nanomaterials 2024, 14(11), 909; https://doi.org/10.3390/nano14110909 - 22 May 2024
Viewed by 1060
Abstract
The growth of high-composition GeSn films in the future will likely be guided by algorithms. In this study, we show how a logarithmic-based algorithm can be used to obtain high-quality GeSn compositions up to 16% on GaAs (001) substrates via molecular beam epitaxy. [...] Read more.
The growth of high-composition GeSn films in the future will likely be guided by algorithms. In this study, we show how a logarithmic-based algorithm can be used to obtain high-quality GeSn compositions up to 16% on GaAs (001) substrates via molecular beam epitaxy. Herein, we use composition targeting and logarithmic Sn cell temperature control to achieve linearly graded pseudomorph Ge1−xSnx compositions up to 10% before partial relaxation of the structure and a continued gradient up to 16% GeSn. In this report, we use X-ray diffraction, simulation, secondary ion mass spectrometry, and atomic force microscopy to analyze and demonstrate some of the possible growths that can be produced with the enclosed algorithm. This methodology of growth is a major step forward in the field of GeSn development and the first ever demonstration of algorithmically driven, linearly graded GeSn films. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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21 pages, 10710 KiB  
Article
Effects of Laser Treatment of Terbium-Doped Indium Oxide Thin Films and Transistors
by Rihui Yao, Dingrong Liu, Nanhong Chen, Honglong Ning, Guoping Su, Yuexin Yang, Dongxiang Luo, Xianzhe Liu, Haoyan Chen, Muyun Li and Junbiao Peng
Nanomaterials 2024, 14(11), 908; https://doi.org/10.3390/nano14110908 - 22 May 2024
Viewed by 1021
Abstract
In this study, a KrF excimer laser with a high-absorption coefficient in metal oxide films and a wavelength of 248 nm was selected for the post-processing of a film and metal oxide thin film transistor (MOTFT). Due to the poor negative bias illumination [...] Read more.
In this study, a KrF excimer laser with a high-absorption coefficient in metal oxide films and a wavelength of 248 nm was selected for the post-processing of a film and metal oxide thin film transistor (MOTFT). Due to the poor negative bias illumination stress (NBIS) stability of indium gallium zinc oxide thin film transistor (IGZO-TFT) devices, terbium-doped Tb:In2O3 material was selected as the target of this study. The XPS test revealed the presence of both Tb3+ and Tb4+ ions in the Tb:In2O3 film. It was hypothesized that the peak of the laser thermal effect was reduced and the action time was prolonged by the f-f jump of Tb3+ ions and the C-T jump of Tb4+ ions during the laser treatment. Studies related to the treatment of Tb:In2O3 films with different laser energy densities have been carried out. It is shown that as the laser energy density increases, the film density increases, the thickness decreases, the carrier concentration increases, and the optical band gap widens. Terbium has a low electronegativity (1.1 eV) and a high Tb-O dissociation energy (707 kJ/mol), which brings about a large lattice distortion. The Tb:In2O3 films did not show significant crystallization even under laser energy density treatment of up to 250 mJ/cm2. Compared with pure In2O3-TFT, the doping of Tb ions effectively reduces the off-state current (1.16 × 10−11 A vs. 1.66 × 10−12 A), improves the switching current ratio (1.63 × 106 vs. 1.34 × 107) and improves the NBIS stability (ΔVON = −10.4 V vs. 6.4 V) and positive bias illumination stress (PBIS) stability (ΔVON = 8 V vs. 1.6 V). Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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16 pages, 4713 KiB  
Article
Growth of Quasi-Two-Dimensional CrTe Nanoflakes and CrTe/Transition Metal Dichalcogenide Heterostructures
by Dawei Cheng, Jiayi Liu and Bin Wei
Nanomaterials 2024, 14(10), 868; https://doi.org/10.3390/nano14100868 - 16 May 2024
Viewed by 992
Abstract
Two-dimensional (2D) van der Waals layered materials have been explored in depth. They can be vertically stacked into a 2D heterostructure and represent a fundamental way to explore new physical properties and fabricate high-performance nanodevices. However, the controllable and scaled growth of non-layered [...] Read more.
Two-dimensional (2D) van der Waals layered materials have been explored in depth. They can be vertically stacked into a 2D heterostructure and represent a fundamental way to explore new physical properties and fabricate high-performance nanodevices. However, the controllable and scaled growth of non-layered quasi-2D materials and their heterostructures is still a great challenge. Here, we report a selective two-step growth method for high-quality single crystalline CrTe/WSe2 and CrTe/MoS2 heterostructures by adopting a universal CVD strategy with the assistance of molten salt and mass control. Quasi-2D metallic CrTe was grown on pre-deposited 2D transition metal dichalcogenides (TMDC) under relatively low temperatures. A 2D CrTe/TMDC heterostructure was established to explore the interface’s structure using scanning transmission electron microscopy (STEM), and also demonstrate ferromagnetism in a metal–semiconductor CrTe/TMDC heterostructure. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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10 pages, 20028 KiB  
Article
UV/Ozone-Treated and Sol–Gel-Processed Y2O3 Insulators Prepared Using Gelation-Delaying Precursors
by Sangwoo Lee, Yoonjin Cho, Seongwon Heo, Jin-Hyuk Bae, In-Man Kang, Kwangeun Kim, Won-Yong Lee and Jaewon Jang
Nanomaterials 2024, 14(9), 791; https://doi.org/10.3390/nano14090791 - 1 May 2024
Viewed by 1211
Abstract
In this study, a Y2O3 insulator was fabricated via the sol–gel process and the effect of precursors and annealing processes on its electrical performance was studied. Yttrium(III) acetate hydrate, yttrium(III) nitrate tetrahydrate, yttrium isopropoxide oxide, and yttrium(III) tris (isopropoxide) were [...] Read more.
In this study, a Y2O3 insulator was fabricated via the sol–gel process and the effect of precursors and annealing processes on its electrical performance was studied. Yttrium(III) acetate hydrate, yttrium(III) nitrate tetrahydrate, yttrium isopropoxide oxide, and yttrium(III) tris (isopropoxide) were used as precursors, and UV/ozone treatment and high-temperature annealing were performed to obtain Y2O3 films from the precursors. The structure and surface morphologies of the films were characterized via grazing-incidence X-ray diffraction and scanning probe microscopy. Chemical component analysis was performed via X-ray spectroscopy. Electrical insulator characteristics were analyzed based on current density versus electrical field data and frequency-dependent dielectric constants. The Y2O3 films fabricated using the acetate precursor and subjected to the UV/ozone treatment showed a uniform and flat surface morphology with the lowest number of oxygen vacancy defects and unwanted byproducts. The corresponding fabricated capacitors showed the lowest current density (Jg) value of 10−8 A/cm2 at 1 MV/cm and a stable dielectric constant in a frequency range of 20 Hz–100 KHz. At 20 Hz, the dielectric constant was 12.28, which decreased to 10.5 at 105 Hz. The results indicate that high-quality, high-k insulators can be fabricated for flexible electronics using suitable precursors and the suggested low-temperature fabrication methods. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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12 pages, 12095 KiB  
Article
Effect of Electrochemically Active Top Electrode Materials on Nanoionic Conductive Bridge Y2O3 Random-Access Memory
by Yoonjin Cho, Sangwoo Lee, Seongwon Heo, Jin-Hyuk Bae, In-Man Kang, Kwangeun Kim, Won-Yong Lee and Jaewon Jang
Nanomaterials 2024, 14(6), 532; https://doi.org/10.3390/nano14060532 - 16 Mar 2024
Viewed by 1425
Abstract
Herein, sol–gel-processed Y2O3 resistive random-access memory (RRAM) devices were fabricated. The top electrodes (TEs), such as Ag or Cu, affect the electrical characteristics of the Y2O3 RRAM devices. The oxidation process, mobile ion migration speed, and reduction [...] Read more.
Herein, sol–gel-processed Y2O3 resistive random-access memory (RRAM) devices were fabricated. The top electrodes (TEs), such as Ag or Cu, affect the electrical characteristics of the Y2O3 RRAM devices. The oxidation process, mobile ion migration speed, and reduction process all impact the conductive filament formation of the indium–tin–oxide (ITO)/Y2O3/Ag and ITO/Y2O3/Cu RRAM devices. Between Ag and Cu, Cu can easily be oxidized due to its standard redox potential values. However, the conductive filament is easily formed using Ag TEs. After triggering the oxidation process, the formed Ag mobile metal ions can migrate faster inside Y2O3 active channel materials when compared to the formed Cu mobile metal ions. The fast migration inside the Y2O3 active channel materials successfully reduces the SET voltage and improves the number of programming–erasing cycles, i.e., endurance, which is one of the nonvolatile memory parameters. These results elucidate the importance of the electrochemical properties of TEs, providing a deeper understanding of how these factors influence the resistive switching characteristics of metal oxide-based atomic switches and conductive-metal-bridge-filament-based cells. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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20 pages, 3801 KiB  
Article
Isotopic Tracer Study of Initiation of Porosity in Anodic Alumina Formed in Chromic Acid
by Aleksandra Baron-Wiechec and Guocong Lin
Nanomaterials 2024, 14(1), 42; https://doi.org/10.3390/nano14010042 - 22 Dec 2023
Viewed by 875
Abstract
In this paper, we focused on the initiation of porosity in the anodic alumina under galvanostatic conditions in chromic acid, using an 18O isotope tracer. The general concept of the initiation and growth of porous anodic oxide films on metals has undergone [...] Read more.
In this paper, we focused on the initiation of porosity in the anodic alumina under galvanostatic conditions in chromic acid, using an 18O isotope tracer. The general concept of the initiation and growth of porous anodic oxide films on metals has undergone constant development over many years. A mechanism of viscous flow of the oxide from the barrier layer to the pore walls has recently been proposed. In this work, two types of pre-formed oxide films were analysed: pure Al2O3 formed in chromic acid, and a film containing As ions formed in a sodium arsenate solution. Both were anodized in chromic acid for several different time durations. Both pre-formed films contained the oxygen isotope 18O. The locations and quantities of 18O and As were analysed by means of ion accelerator-based methods supported by transmission electron microscopy. The significant difference observed between the two oxide films is in the 18O distribution following the second step of anodization, when compared with galvanostatic anodization in phosphoric or sulfuric acid reported in previous works. From the current experiment, it is evident that a small amount of As in the pre-formed barrier layer appears to alter the ionic conductivity of the film; thus, somehow, it inhibits the movement of oxygen ions ahead of advancing pores during anodization in chromic acid. However, anodising pure alumina film under these conditions does not enhance oxygen movement within the oxide layer. In addition, the tracer stays in the outer part of the growing porous oxide film. A lower-than-expected value for pure alumina enrichment in 18O in the pre-formed films suggests, indirectly, that the pre-formed film may contain hydrogen species, as well as trapped electrons, since no Cr is detected. This may lead to the presence of space charge distribution, which has a dual effect: it both retards the ejection of Al3+ ions and prevents O2− ions from migrating inward. Thus, the negative- and positive-charge distributions might play a role in the initiation of pores via a flow mechanism. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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10 pages, 5579 KiB  
Article
Influences of Cu Doping on the Microstructure, Optical and Resistance Switching Properties of Zinc OxideThin Films
by Jun-Hong Weng, Ming-Cheng Kao, Kai-Huang Chen and Men-Zhe Li
Nanomaterials 2023, 13(19), 2685; https://doi.org/10.3390/nano13192685 - 30 Sep 2023
Cited by 3 | Viewed by 1037
Abstract
Copper-doped zinc oxide films (Zn1−xCuxO) (x = 0, 2%, 4%, 6%) were fabricated on conductive substrates using the sol-gel process. The crystal structure, optical and resistive switching properties of Zn1−xCuxO films are studied and discussed. [...] Read more.
Copper-doped zinc oxide films (Zn1−xCuxO) (x = 0, 2%, 4%, 6%) were fabricated on conductive substrates using the sol-gel process. The crystal structure, optical and resistive switching properties of Zn1−xCuxO films are studied and discussed. RRAM is made using Zn1−xCuxO as the resistive layer. The results show that the (002) peak intensity and grain size of Zn1−xCuxOfilms increase from 0 to 6%. In addition, PL spectroscopy shows that the oxygen vacancy defect density of Zn1−xCuxO films also increases with the increase in Cu. The improved resistive switching performance of the RRAM device can be attributed to the formation of conductive filaments and the destruction of more oxygen vacancies in the Zn1−xCuxO film. Consequently, the RRAM device exhibits a higher low resistance state to high resistance state ratio and an HRS state of higher resistance value. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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10 pages, 5014 KiB  
Article
Nanostructured PbSe Films Deposited by Spray Pyrolysis Using PbSe Colloidal Solutions
by Esteban Díaz-Torres, Jorge Roque, Alma Sofía Arreola-Pina, Manuel Alejandro Pérez-Guzmán, Rebeca Ortega-Amaya and Mauricio Ortega-López
Nanomaterials 2023, 13(18), 2595; https://doi.org/10.3390/nano13182595 - 20 Sep 2023
Viewed by 1142
Abstract
This work describes the spray pyrolysis deposition of PbSe films, using as-prepared PbSe colloids as the starting solution. The PbSe colloids were prepared by using the alkahest approach, where Pb and Se precursors were made to react with the following green polyols: glycerin, [...] Read more.
This work describes the spray pyrolysis deposition of PbSe films, using as-prepared PbSe colloids as the starting solution. The PbSe colloids were prepared by using the alkahest approach, where Pb and Se precursors were made to react with the following green polyols: glycerin, ethylene glycol, and propylene glycol, to subsequently spray them onto glass substrates. The results of the characterization indicated that amine or thiol groups-free and single-phase rock-salt cubic PbSe powder was obtained, producing nanocrystals 16–30 nm in size. X-ray diffraction also showed that the PbSe films containing PbSeO3 and PbO·xH2O as impurity phases were produced during the deposition. The morphology of the powders and films was developed by a self-assembly process, in which the primary PbSe nanoparticles self-assemble to produce peanut-like microstructures. Additionally, a non-continuous and porous feature was formed in the thick films. Certain films revealed optical structures characterized by broad- and low-intensity bands resembling an exciton-like behavior. This could be attributed to the presence of nanocrystals with a size less than the Bohr radius, indicating reminiscent quantum effects. The results suggest that the usage of colloidal dispersions as spray solutions represents an effective approach to forming PbSe films, as well as that the synthesis method allows for the elimination of thiol and amine groups before deposition, significantly simplifying the process. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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16 pages, 4964 KiB  
Article
Measurement of Thermal Stress by X-ray Nano-Diffraction in (111)-Oriented Nanotwinned Cu Bumps for Cu/SiO2 Hybrid Joints
by Wei-You Hsu, Shih-Chi Yang, You-Yi Lin, Wan-Zhen Hsieh, King-Ning Tu, Wei-Lan Chiu, Hsiang-Hung Chang, Ching-Yu Chiang and Chih Chen
Nanomaterials 2023, 13(17), 2448; https://doi.org/10.3390/nano13172448 - 29 Aug 2023
Cited by 5 | Viewed by 1589
Abstract
X-ray nanodiffraction was used to measure the thermal stress of 10 µm nanotwinned Cu bumps in Cu/SiO2 hybrid structures at −55 °C, 27 °C, 100 °C, 150 °C, and 200 °C. Bonding can be achieved without externally applied compression. The X-ray beam [...] Read more.
X-ray nanodiffraction was used to measure the thermal stress of 10 µm nanotwinned Cu bumps in Cu/SiO2 hybrid structures at −55 °C, 27 °C, 100 °C, 150 °C, and 200 °C. Bonding can be achieved without externally applied compression. The X-ray beam size is about 100 nm in diameter. The Cu bump is dominated by (111) oriented nano-twins. Before the hybrid bonding, the thermal stress in Cu bumps is compressive and remains compressive after bonding. The average stress in the bonded Cu joint at 200 °C is as large as −169.1 MPa. In addition, using the strain data measured at various temperatures, one can calculate the effective thermal expansion coefficient (CTE) for the 10 µm Cu bumps confined by the SiO2 dielectrics. This study reports a useful approach on measuring the strain and stress in oriented metal bumps confined by SiO2 dielectrics. The results also provide a deeper understanding on the mechanism of hybrid bonding without externally applied compression. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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13 pages, 5607 KiB  
Article
Activation Energy and Bipolar Switching Properties for the Co-Sputtering of ITOX:SiO2 Thin Films on Resistive Random Access Memory Devices
by Kai-Huang Chen, Chien-Min Cheng, Na-Fu Wang and Ming-Cheng Kao
Nanomaterials 2023, 13(15), 2179; https://doi.org/10.3390/nano13152179 - 26 Jul 2023
Viewed by 1214
Abstract
Activation energy, bipolar resistance switching behavior, and the electrical conduction transport properties of ITOX:SiO2 thin film resistive random access memory (RRAM) devices were observed and discussed. The ITOX:SiO2 thin films were prepared using a co-sputtering deposition method [...] Read more.
Activation energy, bipolar resistance switching behavior, and the electrical conduction transport properties of ITOX:SiO2 thin film resistive random access memory (RRAM) devices were observed and discussed. The ITOX:SiO2 thin films were prepared using a co-sputtering deposition method on the TiN/Si substrate. For the RRAM device structure fabrication, an Al/ITOX:SiO2/TiN/Si structure was prepared by using aluminum for the top electrode and a TiN material for the bottom electrode. In addition, grain growth, defect reduction, and RRAM device performance of the ITOX:SiO2 thin film for the various oxygen gas flow conditions were observed and described. Based on the I-V curve measurements of the RRAM devices, the turn on-off ratio and the bipolar resistance switching properties of the Al/ITOX:SiO2/TiN/Si RRAM devices in the set and reset states were also obtained. At low operating voltages and high resistance values, the conductance mechanism exhibits hopping conduction mechanisms for set states. Moreover, at high operating voltages, the conductance mechanism behaves as an ohmic conduction current mechanism. Finally, the Al/ITOX:SiO2/TiN/Si RRAM devices demonstrated memory window properties, bipolar resistance switching behavior, and nonvolatile characteristics for next-generation nonvolatile memory applications. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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10 pages, 2173 KiB  
Article
Intergranular Spin Dependent Tunneling Dominated Magnetoresistance in Helimagnetic Manganese Phosphide Thin Films
by Baleeswaraiah Muchharla, Richa Pokharel Madhogaria, Derick Detellem, Chang-Ming Hung, Amit Chanda, Nivarthana W. Y. A. Y. Mudiyanselage, Anh Tuan Duong, Minh-Tuan Trinh, Sarath Witanachchi and Manh-Huong Phan
Nanomaterials 2023, 13(9), 1478; https://doi.org/10.3390/nano13091478 - 26 Apr 2023
Viewed by 1327
Abstract
Helical magnets are emerging as a novel class of materials for spintronics and sensor applications; however, research on their charge- and spin-transport properties in a thin film form is less explored. Herein, we report the temperature and magnetic field-dependent charge transport properties of [...] Read more.
Helical magnets are emerging as a novel class of materials for spintronics and sensor applications; however, research on their charge- and spin-transport properties in a thin film form is less explored. Herein, we report the temperature and magnetic field-dependent charge transport properties of a highly crystalline MnP nanorod thin film over a wide temperature range (2 K < T < 350 K). The MnP nanorod films of ~100 nm thickness were grown on Si substrates at 500 °C using molecular beam epitaxy. The temperature-dependent resistivity ρ(T) data exhibit a metallic behavior (dρ/dT > 0) over the entire measured temperature range. However, large negative magnetoresistance (Δρ/ρ) of up to 12% is observed below ~50 K at which the system enters a stable helical (screw) magnetic state. In this temperature regime, the Δρ(H)/ρ(0) dependence also shows a magnetic field-manipulated CONE + FAN phase coexistence. The observed magnetoresistance is dominantly governed by the intergranular spin dependent tunneling mechanism. These findings pinpoint a correlation between the transport and magnetism in this helimagnetic system. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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15 pages, 3644 KiB  
Article
Nanostructures Stacked on Hafnium Oxide Films Interfacing Graphene and Silicon Oxide Layers as Resistive Switching Media
by Tauno Kahro, Kristina Raudonen, Joonas Merisalu, Aivar Tarre, Peeter Ritslaid, Aarne Kasikov, Taivo Jõgiaas, Tanel Käämbre, Markus Otsus, Jekaterina Kozlova, Harry Alles, Aile Tamm and Kaupo Kukli
Nanomaterials 2023, 13(8), 1323; https://doi.org/10.3390/nano13081323 - 9 Apr 2023
Viewed by 2101
Abstract
SiO2 films were grown to thicknesses below 15 nm by ozone-assisted atomic layer deposition. The graphene was a chemical vapor deposited on copper foil and transferred wet-chemically to the SiO2 films. On the top of the graphene layer, either continuous HfO [...] Read more.
SiO2 films were grown to thicknesses below 15 nm by ozone-assisted atomic layer deposition. The graphene was a chemical vapor deposited on copper foil and transferred wet-chemically to the SiO2 films. On the top of the graphene layer, either continuous HfO2 or SiO2 films were grown by plasma-assisted atomic layer deposition or by electron beam evaporation, respectively. Micro-Raman spectroscopy confirmed the integrity of the graphene after the deposition processes of both the HfO2 and SiO2. Stacked nanostructures with graphene layers intermediating the SiO2 and either the SiO2 or HfO2 insulator layers were devised as the resistive switching media between the top Ti and bottom TiN electrodes. The behavior of the devices was studied comparatively with and without graphene interlayers. The switching processes were attained in the devices supplied with graphene interlayers, whereas in the media consisting of the SiO2-HfO2 double layers only, the switching effect was not observed. In addition, the endurance characteristics were improved after the insertion of graphene between the wide band gap dielectric layers. Pre-annealing the Si/TiN/SiO2 substrates before transferring the graphene further improved the performance. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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16 pages, 3242 KiB  
Article
Enhanced Magnetism and Anomalous Hall Transport through Two-Dimensional Tungsten Disulfide Interfaces
by Chang-Ming Hung, Diem Thi-Xuan Dang, Amit Chanda, Derick Detellem, Noha Alzahrani, Nalaka Kapuruge, Yen T. H. Pham, Mingzu Liu, Da Zhou, Humberto R. Gutierrez, Darío A. Arena, Mauricio Terrones, Sarath Witanachchi, Lilia M. Woods, Hariharan Srikanth and Manh-Huong Phan
Nanomaterials 2023, 13(4), 771; https://doi.org/10.3390/nano13040771 - 18 Feb 2023
Cited by 3 | Viewed by 2616
Abstract
The magnetic proximity effect (MPE) has recently been explored to manipulate interfacial properties of two-dimensional (2D) transition metal dichalcogenide (TMD)/ferromagnet heterostructures for use in spintronics and valleytronics. However, a full understanding of the MPE and its temperature and magnetic field evolution in these [...] Read more.
The magnetic proximity effect (MPE) has recently been explored to manipulate interfacial properties of two-dimensional (2D) transition metal dichalcogenide (TMD)/ferromagnet heterostructures for use in spintronics and valleytronics. However, a full understanding of the MPE and its temperature and magnetic field evolution in these systems is lacking. In this study, the MPE has been probed in Pt/WS2/BPIO (biphase iron oxide, Fe3O4 and α-Fe2O3) heterostructures through a comprehensive investigation of their magnetic and transport properties using magnetometry, four-probe resistivity, and anomalous Hall effect (AHE) measurements. Density functional theory (DFT) calculations are performed to complement the experimental findings. We found that the presence of monolayer WS2 flakes reduces the magnetization of BPIO and hence the total magnetization of Pt/WS2/BPIO at T > ~120 K—the Verwey transition temperature of Fe3O4 (TV). However, an enhanced magnetization is achieved at T < TV. In the latter case, a comparative analysis of the transport properties of Pt/WS2/BPIO and Pt/BPIO from AHE measurements reveals ferromagnetic coupling at the WS2/BPIO interface. Our study forms the foundation for understanding MPE-mediated interfacial properties and paves a new pathway for designing 2D TMD/magnet heterostructures for applications in spintronics, opto-spincaloritronics, and valleytronics. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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11 pages, 5420 KiB  
Article
Bipolar Switching Properties of the Transparent Indium Tin Oxide Thin Film Resistance Random Access Memories
by Kai-Huang Chen, Chien-Min Cheng, Mei-Li Chen and Yi-Yun Pan
Nanomaterials 2023, 13(4), 688; https://doi.org/10.3390/nano13040688 - 10 Feb 2023
Cited by 6 | Viewed by 1608
Abstract
In this study, the bipolar switching properties and electrical conduction behaviors of the ITO thin films RRAM devices were investigated. For the transparent RRAM devices structure, indium tin oxide thin films were deposited by using the RF magnetron sputtering method on the ITO/glass [...] Read more.
In this study, the bipolar switching properties and electrical conduction behaviors of the ITO thin films RRAM devices were investigated. For the transparent RRAM devices structure, indium tin oxide thin films were deposited by using the RF magnetron sputtering method on the ITO/glass substrate. For the ITO/ITOX/ITO/glass (MIM) structure, an indium tin oxide thin film top electrode was prepared to form the transparent RRAM devices. From the experimental results, the 102 On/Off memory ratio and bipolar switching cycling properties for set/reset stable states were found and discussed. All transparent RRAM devices exhibited the obvious memory window and low set voltage for the switching times of 120 cycles. The electrical transport mechanisms were dominated by the ohmic contact and space charge limit conduction (SCLC) models for set and reset states. Finally, the transmittances properties of the transparent ITO/ITOX/ITO RRAM devices for the different oxygen growth procedures were about 90% according to the UV–Vis spectrophotometer for the visible wavelength range. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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16 pages, 7194 KiB  
Article
Influence of Isothermal Annealing on Microstructure, Morphology and Oxidation Behavior of AlTiSiN/TiSiN Nanocomposite Coatings
by Patrik Šulhánek, Libor Ďuriška, Marián Palcut, Paulína Babincová, Martin Sahul, Ľubomír Čaplovič, Martin Kusý, Ľubomír Orovčík, Štefan Nagy, Leonid Satrapinskyy, Marián Haršáni and Ivona Černičková
Nanomaterials 2023, 13(3), 474; https://doi.org/10.3390/nano13030474 - 24 Jan 2023
Cited by 3 | Viewed by 1990
Abstract
The present work investigates the influence of isothermal annealing on the microstructure and oxidation behavior of nanocomposite coatings. AlTiSiN/TiSiN coatings with TiSiN adhesive layer were deposited onto a high-speed steel substrate via physical vapor deposition. The coatings were investigated in the as-deposited state [...] Read more.
The present work investigates the influence of isothermal annealing on the microstructure and oxidation behavior of nanocomposite coatings. AlTiSiN/TiSiN coatings with TiSiN adhesive layer were deposited onto a high-speed steel substrate via physical vapor deposition. The coatings were investigated in the as-deposited state as well as after annealing in air at 700, 800, 900 and 1000 °C, respectively. The microstructure and morphology of the coatings were observed using scanning electron microscopy and transmission electron microscopy. The chemical composition and presence of oxidation products were studied by energy-dispersive X-ray spectroscopy. The phase identification was performed by means of X-ray diffraction. In the microstructure of the as-deposited coating, the (Ti1−xAlx)N particles were embedded in an amorphous Si3N4 matrix. TiO2 and SiO2 were found at all annealing temperatures, and Al2O3 was additionally identified at 1000 °C. It was found that, with increasing annealing temperature, the thickness of the oxide layer increased, and its morphology and chemical composition changed. At 700 and 800 °C, a Ti-Si-rich surface oxide layer was formed. At 900 and 1000 °C, an oxidized part of the coating was observed in addition to the surface oxide layer. Compared to the as-deposited sample, the oxidized samples exhibited considerably worse mechanical properties. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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9 pages, 3216 KiB  
Article
First Order Rate Law Analysis for Reset State in Vanadium Oxide Thin Film Resistive Random Access Memory Devices
by Kai-Huang Chen, Chien-Min Cheng, Na-Fu Wang, Hsiao-Wen Hung, Cheng-Ying Li and Sean Wu
Nanomaterials 2023, 13(1), 198; https://doi.org/10.3390/nano13010198 - 1 Jan 2023
Cited by 4 | Viewed by 2146
Abstract
In the reset state, the decay reaction mechanism and bipolar switching properties of vanadium oxide thin film RRAM devices for LRS/HRS are investigated and discussed here. To discover the properties of I-V switching curves, the first order rate law behaviors of the reset [...] Read more.
In the reset state, the decay reaction mechanism and bipolar switching properties of vanadium oxide thin film RRAM devices for LRS/HRS are investigated and discussed here. To discover the properties of I-V switching curves, the first order rate law behaviors of the reset state between the resistant variety properties and the reaction time were observed. To verify the decay reaction mechanism in the reset state, vanadium oxide thin films from RRAM devices were measured by different constant voltage sampling and exhibited the same decay reaction rate constant. Finally, the electrical conduction transfer mechanism and metallic filament forming model described by I-V switching properties of the RRAM devices were proven and investigated. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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Review

Jump to: Research

23 pages, 5726 KiB  
Review
A Review on Strain Study of Cuprate Superconductors
by Jian Zhang, Haiyan Wu, Guangzhen Zhao, Lu Han and Jun Zhang
Nanomaterials 2022, 12(19), 3340; https://doi.org/10.3390/nano12193340 - 25 Sep 2022
Cited by 7 | Viewed by 3157
Abstract
Cuprate superconductors have attracted extensive attention due to their broad promising application prospects. Among the factors affecting superconductivity, the effect of strain cannot be ignored, which can significantly enhance or degrade superconductivity. In this review, we discuss and summarize the methods of applying [...] Read more.
Cuprate superconductors have attracted extensive attention due to their broad promising application prospects. Among the factors affecting superconductivity, the effect of strain cannot be ignored, which can significantly enhance or degrade superconductivity. In this review, we discuss and summarize the methods of applying strain to cuprate superconductors, strain measurement techniques, and the influence of strain on superconductivity. Among them, we pay special attention to the study of strain in high–temperature superconducting (HTS) films and coating. We expect this review can guide further research in the field of cuprate superconductors. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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