Topic Editors

Department of Applied Physics, Instituto Regional de Investigación Científica Aplicada (IRICA), University of Castilla-La Mancha, 13071 Ciudad Real, Spain
Instituto de Nanociencia y Materiales de Aragón, CSIC-Universidad de Zaragoza, Facultad de Ciencias, 50009 Zaragoza, Spain
Centro de Investigacion en Materiales Avanzados, Chihuahua, Mexico

Advances in Functional Thin Films

Abstract submission deadline
31 July 2024
Manuscript submission deadline
30 September 2024
Viewed by
21590

Topic Information

Dear Colleagues,

Thin films (i.e., layers of materials with thickness in the range from nanometers to micrometers) offer exceptional functional properties compared with bulk materials and have therefore been extensively used in the last few years. Herein, we invite authors to contribute their original research articles or comprehensive review articles covering the most recent progress and new developments in the synthesis, patterning, and utilization of functional thin films, including the materials used, improvements in the deposition and processing techniques, enhancements in patterning methods, applications and so on. The article types invited include full papers, communications, and reviews. Potential topics include but are not limited to:

  • Fabrication of ultrathin and thin films;
  • Characterization of ultrathin and thin films;
  • Multilayers and other related nanostructures;
  • Modeling of thin films and multilayers;
  • Electronic, spintronic, and optoelectronic applications of thin films;
  • Energy-related applications of thin films;
  • Innovative materials for their use in ultrathin and thin films.

Dr. Ricardo López Antón
Prof. Dr. Jose Maria De Teresa
Dr. Sion Federico Olive Méndez
Topic Editors

Keywords

  • ultrathin films
  • thin films
  • characterization
  • coatings
  • energy
  • environmental applications
  • analytical applications
  • spintronics
  • healthcare
  • materials science
  • nanotechnology
  • fuel cells
  • optoelectronics
  • solar cells
  • sensors and biosensors, lab-on-a-chip devices
  • thin film deposition
  • lithography
  • applications

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Coatings
coatings
3.4 4.7 2011 13.8 Days CHF 2600 Submit
Materials
materials
3.4 5.2 2008 13.9 Days CHF 2600 Submit
Membranes
membranes
4.2 4.4 2011 13.6 Days CHF 2700 Submit
Nanomaterials
nanomaterials
5.3 7.4 2010 13.6 Days CHF 2900 Submit
Solar
solar
- - 2021 16.9 Days CHF 1000 Submit
Colloids and Interfaces
colloids
2.4 4.8 2017 27.6 Days CHF 1600 Submit

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Published Papers (22 papers)

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19 pages, 6054 KiB  
Article
MnO/ZnO:Zn Thin-Film Frequency Adaptive Heterostructure for Future Sustainable Memristive Systems
by Karen A. Neri-Espinoza, José A. Andraca-Adame, Miguel A. Domínguez-Crespo, Francisco Gutiérrez-Galicia, Roberto Baca-Arroyo, Héctor J. Dorantes-Rosales and Ramón Peña-Sierra
Nanomaterials 2024, 14(8), 659; https://doi.org/10.3390/nano14080659 - 10 Apr 2024
Viewed by 360
Abstract
In recent years, advances in materials engineering based on adaptive electronics have found a new paradigm to optimize drawbacks in signal processing. A two-layer MnO/ZnO:Zn heterostructure envisioned for frequency adaptive electronic signal processing is synthesized by sputtering, where the use of internal states [...] Read more.
In recent years, advances in materials engineering based on adaptive electronics have found a new paradigm to optimize drawbacks in signal processing. A two-layer MnO/ZnO:Zn heterostructure envisioned for frequency adaptive electronic signal processing is synthesized by sputtering, where the use of internal states allows reconfigurability to obtain new operating modes at different frequency input signals. X-ray diffraction (XRD) analysis is performed on each layer, revealing a cubic structure for MnO and a hexagonal structure for ZnO:Zn with preferential growth in [111] and [002] directions, respectively. Scanning electron microscope (SEM) micrographs show that the surface of both materials is homogeneous and smooth. The thickness for each layer is determined to be approximately 106.3 nm for MnO, 119.3 nm for ZnO:Zn and 224.1 nm for the MnO/ZnO:Zn structure. An electrical characterisation with an oscilloscope and signal generator was carried out to obtain the time-response signals and current-voltage (I–V) curves, where no degradation is detected when changing frequencies within the range of 100 Hz to 1 MHz. An equivalent circuit is proposed to explain the effects in the interface. Measurements of switching speeds from high resistance state (HRS) to low resistance state (LRS) at approximately 17 ns, highlight the device’s rapid adaptability, and an estimated switching ratio of approximately 2 × 104 indicates its efficiency as a memristive component. Finally, the MnO/ZnO:Zn heterojunction delivers states that are stable, repeatable, and reproducible, demonstrating how the interaction of the materials can be utilised in adaptive device applications by applying frequencies and internal states to create new and innovative design schematics, thus reducing the number of components/connections in a system for future sustainable electronics. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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14 pages, 10357 KiB  
Article
Thermal Stability and Crystallization Processes of Pd78Au4Si18 Thin Films Visualized via In Situ TEM
by Bingjiao Yu, Rui Zhao, Zhen Lu, Hangbo Su, Binye Liang, Bingjie Liu, Chunlan Ma, Yan Zhu and Zian Li
Nanomaterials 2024, 14(7), 635; https://doi.org/10.3390/nano14070635 - 05 Apr 2024
Viewed by 464
Abstract
Amorphous alloys or metallic glasses (MGs) thin films have attracted extensive attention in various fields due to their unique functional properties. Here, we use in situ heating transmission electron microscopy (TEM) to investigate the thermal stability and crystallization behavior of Pd-Au-Si thin films [...] Read more.
Amorphous alloys or metallic glasses (MGs) thin films have attracted extensive attention in various fields due to their unique functional properties. Here, we use in situ heating transmission electron microscopy (TEM) to investigate the thermal stability and crystallization behavior of Pd-Au-Si thin films prepared by a pulsed laser deposition (PLD) method. Upon heating treatment inside a TEM, we trace the structural changes in the Pd-Au-Si thin films through directly recording high-resolution images and diffraction patterns at different temperatures. TEM observations reveal that the Pd-Au-Si thin films started to nucleate with small crystalline embryos uniformly distributed in the glassy matrix upon approaching the glass transition temperature Tg=625K, and subsequently, the growth of crystalline nuclei into sub-10 nm Pd-Si nanocrystals commenced. Upon further increasing the temperature to 673K, the thin films transformed to micro-sized patches of stacking-faulty lamellae that further crystallized into Pd9Si2 and Pd3Si intermetallic compounds. Interestingly, with prolonged thermal heating at elevated temperatures, the Pd9Si2 transformed to Pd3Si. Simultaneously, the solute Au atoms initially dissolved in glassy alloys and eventually precipitated out of the Pd9Si2 and Pd3Si intermetallics, forming nearly spherical Au nanocrystals. Our TEM results reveal the unique thermal stability and crystallization processes of the PLD-prepared Pd-Au-Si thin films as well as demonstrate a possibility of producing a large quantity of pure nanocrystals out of amorphous solids for various applications. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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12 pages, 2855 KiB  
Article
Monolithic Use of Inert Gas for Highly Transparent and Conductive Indium Tin Oxide Thin Films
by Hessa I. Alabdan, Fahad M. Alsahli, Shubhranshu Bhandari and Tapas Mallick
Nanomaterials 2024, 14(7), 565; https://doi.org/10.3390/nano14070565 - 24 Mar 2024
Viewed by 587
Abstract
Due to its excellent electrical conductivity, high transparency in the visible spectrum, and exceptional chemical stability, indium tin oxide (ITO) has become a crucial material in the fields of optoelectronics and nanotechnology. This article provides a thorough analysis of growing ITO thin films [...] Read more.
Due to its excellent electrical conductivity, high transparency in the visible spectrum, and exceptional chemical stability, indium tin oxide (ITO) has become a crucial material in the fields of optoelectronics and nanotechnology. This article provides a thorough analysis of growing ITO thin films with various thicknesses to study the impact of thickness on their electrical, optical, and physical properties for solar-cell applications. ITO was prepared through radio frequency (RF) magnetron sputtering using argon gas with no alteration in temperature or changes in substrate heating, followed with annealing in a tube furnace under inert conditions. An investigation of the influence of thickness on the optical, electrical, and physical properties of the films was conducted. We found that the best thickness for ITO thin films was 100 nm in terms of optical, electrical, and physical properties. To gain full comprehension of the impact on electrical properties, the different samples were characterized using a four-point probe and, interestingly, we found a high conductivity in the range of 1.8–2 × 106 S/m, good resistivity that did not exceed 1–2 × 10−6 Ωm, and a sheet resistance lower than 16 Ω sq−1. The transparency values found using a spectrophotometer reached values beyond 85%, which indicates the high purity of the thin films. Atomic force microscopy indicated a smooth morphology with low roughness values for the films, indicating an adequate transitioning of the charges on the surface. Scanning electron microscopy was used to study the actual thicknesses and the morphology, through which we found no cracks or fractures, which implied excellent deposition and annealing. The X-ray diffraction microscopy results showed a high purity of the crystals, as the peaks (222), (400), (440), and (622) of the crystallographic plane reflections were dominant, which confirmed the existence of the faced-center cubic lattice of ITO. This work allowed us to design a method for producing excellent ITO thin films for solar-cell applications. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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15 pages, 8939 KiB  
Article
Optimized Tribological Performance of Nitrogen-Doped Diamond-like Carbon Films on NBR: Influence of Bias Voltage of DC Magnetron Sputtering
by Tao Yang, Changxin Han, Qiaoyuan Deng and Feng Wen
Nanomaterials 2024, 14(7), 564; https://doi.org/10.3390/nano14070564 - 24 Mar 2024
Viewed by 739
Abstract
In this research, nitrogen-doped diamond-like carbon (N-DLC) coatings were deposited on Nitrile Butadiene Rubber (NBR) substrates using direct current magnetron sputtering (DC-MS) under varying bias voltages. This study aimed to explore environmentally friendly, low-wear, and non-lubricating seal coatings to enhance the durability of [...] Read more.
In this research, nitrogen-doped diamond-like carbon (N-DLC) coatings were deposited on Nitrile Butadiene Rubber (NBR) substrates using direct current magnetron sputtering (DC-MS) under varying bias voltages. This study aimed to explore environmentally friendly, low-wear, and non-lubricating seal coatings to enhance the durability of rubber sealing products, which predominantly operate under dynamic sliding conditions. By reducing the coefficient of friction (CoF), the friction and wear on rubber products can be significantly minimized, extending their lifespan. This investigation thoroughly examined the microstructure, mechanical properties, and tribological behavior of the N-DLC films. Among the coatings, the one produced at a bias voltage of −50 V demonstrated superior hardness, elastic modulus, and the lowest CoF in comparison to those prepared with 0, −100, and −200 bias voltages. This optimal combination of properties resulted in an exceptionally low wear rate of 10−9 for the film deposited at −50 V, indicating its outstanding wear resistance. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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17 pages, 7900 KiB  
Article
Combined Terahertz Pulsed Imaging and Optical Coherence Tomography Detection Method for Multiple Defects in Thermal Barrier Coatings
by Manting Luo, Shuncong Zhong, Yi Huang, Zhenghao Zhang and Wanli Tu
Coatings 2024, 14(4), 380; https://doi.org/10.3390/coatings14040380 - 24 Mar 2024
Viewed by 656
Abstract
While thermal barrier coatings (TBCs) are being sprayed onto aero-engine turbine blades, or while the engine blade is working, high temperatures and strong impact forces will damage TBCs under thermal cycles, resulting in the coating peeling off from the blades. The current method [...] Read more.
While thermal barrier coatings (TBCs) are being sprayed onto aero-engine turbine blades, or while the engine blade is working, high temperatures and strong impact forces will damage TBCs under thermal cycles, resulting in the coating peeling off from the blades. The current method of using ECT, IRT, or another method alone cannot achieve the real-time detection of coating defects with both high precision and high penetration power. Two detection methods, namely, terahertz pulsed imaging (TPI) and optical coherence tomography (OCT), were combined to evaluate typical defects observed in TBCs (including internal debonding cracks, surface high-temperature cracks, and surface etched cracks). The results showed that the OCT system successfully obtained the micron-level axial resolution, but the detection depth of the OCT system was limited. The TPI system achieved a higher penetration depth than OCT—hence, it can be used for the nondestructive detection and evaluation of the internal debonding defects in the sample—but its resolution needs to be improved. Following this conclusion, a method is proposed using TPI and OCT concurrently for the nondestructive testing and quantitative evaluation of TBCs on etched cracks, thus achieving progress both in terms of depth and resolution. In our experiment, defects with a depth of 519 μm and a width of 100 μm were measured. The proposed method is suitable for situations where multiple defects in TBC samples of blades need to be detected simultaneously during the working process. When there are defects deep inside the sample, more small cracks on the surface can be evaluated to achieve a combination of depth and accuracy. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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26 pages, 4068 KiB  
Review
Using Deep Eutectic Solvent-Assisted Plating Baths to Electrodeposit Composite Coatings: A Review
by Vyacheslav Protsenko
Coatings 2024, 14(4), 375; https://doi.org/10.3390/coatings14040375 - 22 Mar 2024
Viewed by 685
Abstract
This review provides a systematic analysis of the literature data on the electrodeposition of composite coatings using plating baths based on a new generation of room-temperature ionic liquids known as deep eutectic solvents (DESs). Such systems offer several advantages over traditionally used aqueous [...] Read more.
This review provides a systematic analysis of the literature data on the electrodeposition of composite coatings using plating baths based on a new generation of room-temperature ionic liquids known as deep eutectic solvents (DESs). Such systems offer several advantages over traditionally used aqueous electrolytes and organic solvent-based electrolytes. The colloidal–chemical properties of suspension and colloidal electrolytes for composite deposition are thoroughly examined. New theories describing the kinetics of the co-deposition of composite layers are characterized. The kinetics and mechanisms of electrochemical deposition processes of composite coatings with metallic matrices are discussed. Case studies regarding the electrodeposition of composite coatings based on electrodeposited copper, silver, zinc, tin, nickel, cobalt, and chromium from DES-assisted electroplating baths are described and systematized. The main prospective directions for further research in the discussed scientific area are highlighted. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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11 pages, 2572 KiB  
Article
Synthesized PANI/CeO2 Nanocomposite Films for Enhanced Anti-Corrosion Performance
by Ahmad M. Alsaad, Mohannad Al-Hmoud, Taha M. Rababah, Mohammad W. Marashdeh, Mamduh J. Aljaafreh, Sharif Abu Alrub, Ayed Binzowaimil and Ahmad Telfah
Nanomaterials 2024, 14(6), 526; https://doi.org/10.3390/nano14060526 - 15 Mar 2024
Viewed by 643
Abstract
This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic [...] Read more.
This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film is measured to be 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S·cm−1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S·cm−1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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17 pages, 8020 KiB  
Article
Heterojunction Devices Fabricated from Sprayed n-Type Ga2O3, Combined with Sputtered p-Type NiO and Cu2O
by Theodoros Dimopoulos, Rachmat Adhi Wibowo, Stefan Edinger, Maximilian Wolf and Thomas Fix
Nanomaterials 2024, 14(3), 300; https://doi.org/10.3390/nano14030300 - 01 Feb 2024
Viewed by 864
Abstract
This work reports on the properties of heterojunctions consisting of n-type Ga2O3 layers, deposited using ultrasonic spray pyrolysis at high temperature from water-based solution, combined with p-type NiO and Cu2O counterparts, deposited by radio frequency and [...] Read more.
This work reports on the properties of heterojunctions consisting of n-type Ga2O3 layers, deposited using ultrasonic spray pyrolysis at high temperature from water-based solution, combined with p-type NiO and Cu2O counterparts, deposited by radio frequency and reactive, direct-current magnetron sputtering, respectively. After a comprehensive investigation of the properties of the single layers, the fabricated junctions on indium tin oxide (ITO)-coated glass showed high rectification, with an open circuit voltage of 940 mV for Ga2O3/Cu2O and 220 mV for Ga2O3/NiO under simulated solar illumination. This demonstrates in praxis the favorable band alignment between the sprayed Ga2O3 and Cu2O, with small conduction band offset, and the large offsets anticipated for both energy bands in the case of Ga2O3/NiO. Large differences in the ideality factors between the two types of heterojunctions were observed, suggestive of distinctive properties of the heterointerface. Further, it is shown that the interface between the high-temperature-deposited Ga2O3 and the ITO contact does not impede electron transport, opening new possibilities for the design of solar cell and optoelectronic device architectures. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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12 pages, 2277 KiB  
Article
Evaluation of Sputtering Processes in Strontium Iridate Thin Films
by Víctor Fuentes, Lluis Balcells, Zorica Konstantinović, Benjamín Martínez and Alberto Pomar
Nanomaterials 2024, 14(3), 242; https://doi.org/10.3390/nano14030242 - 23 Jan 2024
Viewed by 625
Abstract
The growth of epitaxial thin films from the Ruddlesden–Popper series of strontium iridates by magnetron sputtering is analyzed. It was found that, even using a non-stoichiometric target, the films formed under various conditions were consistently of the perovskite-like n = ∞ SrIrO3 [...] Read more.
The growth of epitaxial thin films from the Ruddlesden–Popper series of strontium iridates by magnetron sputtering is analyzed. It was found that, even using a non-stoichiometric target, the films formed under various conditions were consistently of the perovskite-like n = ∞ SrIrO3 phase, with no evidence of other RP series phases. A detailed inspection of the temperature–oxygen phase diagram underscored that kinetics mechanisms prevail over thermodynamics considerations. The analysis of the angular distribution of sputtered iridium and strontium species indicated clearly different spatial distribution patterns. Additionally, significant backsputtering was detected at elevated temperatures. Thus, it is assumed that the interplay between these two kinetic phenomena is at the origin of the preferential nucleation of the SrIrO3 phase. In addition, strategies for controlling cation stoichiometry off-axis have also been explored. Finally, the long-term stability of the films has been demonstrated. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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18 pages, 5597 KiB  
Review
Perovskite Topological Lasers: A Brand New Combination
by Liangshen Wang, Lijie Wu and Yong Pan
Nanomaterials 2024, 14(1), 28; https://doi.org/10.3390/nano14010028 - 21 Dec 2023
Viewed by 765
Abstract
Nanolasers are the essential components of modern photonic chips due to their low power consumption, high energy efficiency and fast modulation. As nanotechnology has advanced, researchers have proposed a number of nanolasers operating at both wavelength and sub-wavelength scales for application as light [...] Read more.
Nanolasers are the essential components of modern photonic chips due to their low power consumption, high energy efficiency and fast modulation. As nanotechnology has advanced, researchers have proposed a number of nanolasers operating at both wavelength and sub-wavelength scales for application as light sources in photonic chips. Despite the advances in chip technology, the quality of the optical cavity, the operating threshold and the mode of operation of the light source still limit its advanced development. Ensuring high-performance laser operation has become a challenge as device size has been significantly reduced. A potential solution to this problem is the emergence of a novel optical confinement mechanism using photonic topological insulator lasers. In addition, gain media materials with perovskite-like properties have shown great potential for lasers, a role that many other gain materials cannot fulfil. When combined with topological laser modes, perovskite materials offer new possibilities for the operation and emission mechanism of nanolasers. This study introduces the operating mechanism of topological lasers and the optical properties of perovskite materials. It then outlines the key features of their combination and discusses the principles, structures, applications and prospects of perovskite topological lasers, including the scientific hurdles they face. Finally, the future development of low-dimensional perovskite topological lasers is explored. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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16 pages, 3220 KiB  
Article
The Impact of Topological States on the Thermoelectric Performance of p- and n-Type Sb2Te3/Bi2Se3-Multiwalled Carbon Nanotubes Heterostructured Networks
by Jana Andzane, Krisjanis Buks, Elmars Spalva, Andrei Felsharuk and Donats Erts
Coatings 2023, 13(12), 2082; https://doi.org/10.3390/coatings13122082 - 14 Dec 2023
Viewed by 700
Abstract
The resistance and magnetoresistance of flexible thermoelectric p-type Sb2Te3-MWCNT, p-type Bi2Se3-MWCNT, and n-type Bi2Se3-MWCNT heterostructures were studied in the temperature range from 2 K to 300 K to reveal the conductance [...] Read more.
The resistance and magnetoresistance of flexible thermoelectric p-type Sb2Te3-MWCNT, p-type Bi2Se3-MWCNT, and n-type Bi2Se3-MWCNT heterostructures were studied in the temperature range from 2 K to 300 K to reveal the conductance mechanisms governing the thermoelectric properties of these heterostructured networks. It was found that the conductance in heterostructured networks at different temperatures is governed by different processes and components of the networks. This effect was found to be related to the growth mechanisms of the Sb2Te3 and Bi2Se3 nanostructures on the MWCNT networks. At near-room temperatures, the Sb2Te3 and Bi2Se3 nanostructures were found to have the dominant contribution to the total conductance of the p-type Sb2Te3-MWCNT and n-type Bi2Se3-MWCNT networks. In turn, the conduction of p-type Bi2Se3-MWCNT heterostructured networks in a full temperature range and p-type Sb2Te3-MWCNT and n-type Bi2Se3-MWCNT heterostructured networks at temperatures below 30 K was governed by the MWCNTs; however, with the contribution from 2D topological states of Sb2Te3 and Bi2Se3 nanostructures, these were manifested by the weak antilocalization effect (WAL) cusps observed at temperatures below 5–10 K for all heterostructured networks considered in this work. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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16 pages, 4552 KiB  
Article
Radiation Curing of Phosphorus Telomer-Based Coatings Using UV LEDs or Medium-Pressure Mercury Lamp
by Agata Kraśkiewicz and Agnieszka Kowalczyk
Materials 2023, 16(23), 7493; https://doi.org/10.3390/ma16237493 - 04 Dec 2023
Viewed by 904
Abstract
In the presented study, UV LEDs (365 nm) or a medium-pressure mercury lamp (UV-ABC) were verified as UV radiation sources initiating the photocrosslinking process of varnishes based on novel photopolymerizable phosphorus (meth)acrylate oligomers. Coating formulations were composed of (meth)acrylic/styrene telomers with terminal P-atoms [...] Read more.
In the presented study, UV LEDs (365 nm) or a medium-pressure mercury lamp (UV-ABC) were verified as UV radiation sources initiating the photocrosslinking process of varnishes based on novel photopolymerizable phosphorus (meth)acrylate oligomers. Coating formulations were composed of (meth)acrylic/styrene telomers with terminal P-atoms (prepared via a UV phototelomerization process) and different photoinitiators (HAPs, APOs, or APO blends). The kinetics of the UV crosslinking process of the coating formulations depending on UV irradiation and the UV range was investigated by the photo-DSC method. Moreover, the hardness of the varnishes and the conversion of double bonds using the FTIR method were tested. The photopolymerization rate and the photoinitiation index, depending on the type of photoinitiator, were as follows: APOs < APO blends < HAPs. However, the highest coating hardness results were obtained using the least reactive photoinitiator from the APO group, i.e., Omnirad TPOL, or a mixture of three different types of acylphosphine (Omnirad BL 750). The greater effectiveness of the above-mentioned APOs over HAP was also demonstrated when using a UV LED lamp at 365 nm with a low UV dose and UV irradiance, thanks to the presence of phosphoric acid diester in the coating composition, acting as both a telogen and an antioxidant. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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13 pages, 3531 KiB  
Article
Magnetic, Antiferroelectric-like Behavior and Resistance Switching Properties in BiFeO3-CaMnO3 Polycrystalline Thin Films
by Abdelilah Lahmar, Jacem Zidani, Jamal Belhadi, Ilham Hamdi Alaoui, Hussam Musleh, Jehad Asad, Naji Al Dahoudi and Mimoun El Marssi
Materials 2023, 16(23), 7392; https://doi.org/10.3390/ma16237392 - 28 Nov 2023
Viewed by 527
Abstract
The effect of ferromagnetic CaMnO3 (CMO) addition to structural, magnetic, dielectric, and ferroelectric properties of BiFeO3 is presented. X-ray diffraction and Raman investigation allowed the identification of a single pseudocubic perovskite structure. The magnetic measurement showed that the prepared films exhibit [...] Read more.
The effect of ferromagnetic CaMnO3 (CMO) addition to structural, magnetic, dielectric, and ferroelectric properties of BiFeO3 is presented. X-ray diffraction and Raman investigation allowed the identification of a single pseudocubic perovskite structure. The magnetic measurement showed that the prepared films exhibit a ferromagnetic behavior at a low temperature with both coercive field and remnant magnetization increased with increasing CMO content. However, a deterioration of magnetization was observed at room temperature. Ferroelectric study revealed an antiferroelectric-like behavior with a pinched PE hysteresis loop for 5% CMO doping BFO, resulting in low remnant polarization and double hysteresis loops. Whereas, high remnant polarization and coercive field with a likely square hysteresis loop are obtained for 10% CMO addition. Furthermore, a bipolar resistive switching behavior with a threshold voltage of about 1.8 V is observed for high doped film that can be linked to the ferroelectric polarization switching. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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15 pages, 3936 KiB  
Article
Magnetism and Thermal Transport of Exchange-Spring-Coupled La2/3Sr1/3MnO3/La2MnCoO6 Superlattices with Perpendicular Magnetic Anisotropy
by Vitaly Bruchmann-Bamberg, Isabell Weimer, Vladimir Roddatis, Ulrich Ross, Leonard Schüler, Karen P. Stroh and Vasily Moshnyaga
Nanomaterials 2023, 13(21), 2897; https://doi.org/10.3390/nano13212897 - 03 Nov 2023
Cited by 1 | Viewed by 647
Abstract
Superlattices (SLs) comprising layers of a soft ferromagnetic metal La2/3Sr1/3MnO3 (LSMO) with in-plane (IP) magnetic easy axis and a hard ferromagnetic insulator La2MnCoO6 (LMCO, out-of-plane anisotropy) were grown on SrTiO3 (100)(STO) substrates by a [...] Read more.
Superlattices (SLs) comprising layers of a soft ferromagnetic metal La2/3Sr1/3MnO3 (LSMO) with in-plane (IP) magnetic easy axis and a hard ferromagnetic insulator La2MnCoO6 (LMCO, out-of-plane anisotropy) were grown on SrTiO3 (100)(STO) substrates by a metalorganic aerosol deposition technique. Exchange spring magnetic (ESM) behavior between LSMO and LMCO, manifested by a spin reorientation transition of the LSMO layers towards perpendicular magnetic anisotropy below TSR = 260 K, was observed. Further, 3ω measurements of the [(LMCO)9/(LSMO)9]11/STO(100) superlattices revealed extremely low values of the cross-plane thermal conductivity κ(300 K) = 0.32 Wm−1K−1. Additionally, the thermal conductivity shows a peculiar dependence on the applied IP magnetic field, either decreasing or increasing in accordance with the magnetic disorder induced by ESM. Furthermore, both positive and negative magnetoresistance were observed in the SL in the respective temperature regions due to the formation of 90°-Néel domain walls within the ESM, when applying IP magnetic fields. The results are discussed in the framework of electronic contribution to thermal conductivity originating from the LSMO layers. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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10 pages, 4307 KiB  
Article
Low-Temperature Solution-Processed HfZrO Gate Insulator for High-Performance of Flexible LaZnO Thin-Film Transistor
by Yeoungjin Chang, Ravindra Naik Bukke, Jinbaek Bae and Jin Jang
Nanomaterials 2023, 13(17), 2410; https://doi.org/10.3390/nano13172410 - 25 Aug 2023
Cited by 1 | Viewed by 974
Abstract
Metal-oxide-semiconductor (MOS)-based thin-film transistors (TFTs) are gaining significant attention in the field of flexible electronics due to their desirable electrical properties, such as high field-effect mobility (μFE), lower IOFF, and excellent stability under bias stress. TFTs have widespread applications, [...] Read more.
Metal-oxide-semiconductor (MOS)-based thin-film transistors (TFTs) are gaining significant attention in the field of flexible electronics due to their desirable electrical properties, such as high field-effect mobility (μFE), lower IOFF, and excellent stability under bias stress. TFTs have widespread applications, such as printed electronics, flexible displays, smart cards, image sensors, virtual reality (VR) and augmented reality (AR), and the Internet of Things (IoT) devices. In this study, we approach using a low-temperature solution-processed hafnium zirconium oxide (HfZrOx) gate insulator (GI) to improve the performance of lanthanum zinc oxide (LaZnO) TFTs. For the optimization of HfZrO GI, HfZrO films were annealed at 200, 250, and 300 °C. The optimized HfZrO-250 °C GI-based LaZnO TFT shows the μFE of 19.06 cm2V−1s−1, threshold voltage (VTH) of 1.98 V, hysteresis voltage (VH) of 0 V, subthreshold swing (SS) of 256 mV/dec, and ION/IOFF of ~108. The flexible LaZnO TFT with HfZrO-250 °C GI exhibits negligible ΔVTH of 0.25 V under positive-bias-temperature stress (PBTS). The flexible hysteresis-free LaZnO TFTs with HfZrO-250 °C can be widely used for flexible electronics. These enhancements were attributed to the smooth surface morphology and reduced defect density achieved with the HfZrO gate insulator. Therefore, the HfZrO/LaZnO approach holds great promise for next-generation MOS TFTs for flexible electronics. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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17 pages, 5690 KiB  
Article
TiNbN Hard Coating Deposited at Varied Substrate Temperature by Cathodic Arc: Tribological Performance under Simulated Cutting Conditions
by Juan Manuel Gonzalez-Carmona, Claudia Lorena Mambuscay, Carolina Ortega-Portilla, Abel Hurtado-Macias and Jeferson Fernando Piamba
Materials 2023, 16(13), 4531; https://doi.org/10.3390/ma16134531 - 22 Jun 2023
Cited by 5 | Viewed by 1031
Abstract
This study focused on investigating the adhesion and tribological properties of niobium-doped titanium nitride (TiNbN) coatings deposited on D2 steel substrates at various substrate temperatures (Ts) under simulated cutting conditions. X-ray diffraction confirmed the presence of coatings with an FCC crystalline structure, where [...] Read more.
This study focused on investigating the adhesion and tribological properties of niobium-doped titanium nitride (TiNbN) coatings deposited on D2 steel substrates at various substrate temperatures (Ts) under simulated cutting conditions. X-ray diffraction confirmed the presence of coatings with an FCC crystalline structure, where Nb substitutes Ti atoms in the TiN lattice. With increasing Ts, the lattice parameter decreased, and the crystallite material transitioned from flat-like to spherical shapes. Nanoindentation tests revealed an increase in hardness (H) with Ts, while a decrease in the elastic modulus (E) resulted in an improved elastic strain limit for failure (H/E) and plastic deformation resistance (H3/E2), thereby enhancing stiffness and contact elasticity. Adhesion analysis showed critical loads of ~50 N at Ts of 200 and 400 °C, and ~38 N at Ts of 600 °C. Cohesive failures were associated with lateral cracking, while adhesive failures were attributed to chipping spallation. The tribological behavior was evaluated using a pin-on-disk test, which indicated an increase in friction coefficients with Ts, although they remained lower than those of the substrate. Friction and wear were influenced by the surface morphology, facilitating the formation of abrasive particles. However, the absence of coating detachment in the wear tracks suggested that the films were capable of withstanding the load and wear. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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11 pages, 2652 KiB  
Article
Lattice Strain Relaxation and Compositional Control in As-Rich GaAsP/(100)GaAs Heterostructures Grown by MOVPE
by Paola Prete, Daniele Calabriso, Emiliano Burresi, Leander Tapfer and Nico Lovergine
Materials 2023, 16(12), 4254; https://doi.org/10.3390/ma16124254 - 08 Jun 2023
Viewed by 919
Abstract
The fabrication of high-efficiency GaAsP-based solar cells on GaAs wafers requires addressing structural issues arising from the materials lattice mismatch. We report on tensile strain relaxation and composition control of MOVPE-grown As-rich GaAs1−xPx/(100)GaAs heterostructures studied by double-crystal X-ray diffraction [...] Read more.
The fabrication of high-efficiency GaAsP-based solar cells on GaAs wafers requires addressing structural issues arising from the materials lattice mismatch. We report on tensile strain relaxation and composition control of MOVPE-grown As-rich GaAs1−xPx/(100)GaAs heterostructures studied by double-crystal X-ray diffraction and field emission scanning electron microscopy. Thin (80–150 nm) GaAs1−xPx epilayers appear partially relaxed (within 1−12% of the initial misfit) through a network of misfit dislocations along the sample [011] and [011] in plane directions. Values of the residual lattice strain as a function of epilayer thickness were compared with predictions from the equilibrium (Matthews–Blakeslee) and energy balance models. It is shown that the epilayers relax at a slower rate than expected based on the equilibrium model, an effect ascribed to the existence of an energy barrier to the nucleation of new dislocations. The study of GaAs1−xPx composition as a function of the V-group precursors ratio in the vapor during growth allowed for the determination of the As/P anion segregation coefficient. The latter agrees with values reported in the literature for P-rich alloys grown using the same precursor combination. P-incorporation into nearly pseudomorphic heterostructures turns out to be kinetically activated, with an activation energy EA = 1.41 ± 0.04 eV over the entire alloy compositional range. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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16 pages, 46803 KiB  
Article
Investigation of TiO2 Deposit on SiO2 Films: Synthesis, Characterization, and Efficiency for the Photocatalytic Discoloration of Methylene Blue in Aqueous Solution
by Yuliana de Jesús Acosta-Silva, Manuel Toledano-Ayala, Salvador Gallardo-Hernández, Luis A. Godínez and Arturo Méndez-López
Nanomaterials 2023, 13(8), 1403; https://doi.org/10.3390/nano13081403 - 19 Apr 2023
Cited by 3 | Viewed by 1631
Abstract
TiO2-SiO2 thin films were created on Corning glass substrates using a simple method. Nine layers of SiO2 were deposited; later, several layers of TiO2 were deposited, and their influence was studied. Raman spectroscopy, high resolution transmission electron spectroscopy [...] Read more.
TiO2-SiO2 thin films were created on Corning glass substrates using a simple method. Nine layers of SiO2 were deposited; later, several layers of TiO2 were deposited, and their influence was studied. Raman spectroscopy, high resolution transmission electron spectroscopy (HRTEM), an X-ray diffractometer (XRD), ultraviolet-visible spectroscopy (UV-Vis), a scanning electron microscope (SEM), and atomic force microscopy (AFM) were used to describe the sample’s shape, size, composition, and optical characteristics. Photocatalysis was realized through an experiment involving the deterioration of methylene blue (MB) solution exposed to UV-Vis radiation. With the increase of TiO2 layers, the photocatalytic activity (PA) of the thin films showed an increasing trend, and the maximum degradation efficiency of MB by TiO2-SiO2 was 98%, which was significantly higher than that obtained by SiO2 thin films. It was found that an anatase structure was formed at a calcination temperature of 550 °C; phases of brookite or rutile were not observed. Each nanoparticle’s size was 13–18 nm. Due to photo-excitation occurring in both the SiO2 and the TiO2, deep UV light (λ = 232 nm) had to be used as a light source to increase photocatalytic activity. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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10 pages, 2769 KiB  
Article
Threshold-Voltage Extraction Methods for Atomically Deposited Disordered ZnO Thin-Film Transistors
by Minho Yoon
Materials 2023, 16(8), 2940; https://doi.org/10.3390/ma16082940 - 07 Apr 2023
Cited by 2 | Viewed by 2250
Abstract
In this paper, we present a threshold-voltage extraction method for zinc oxide (ZnO) thin-film transistors (TFTs). Bottom-gate atomic-layer-deposited ZnO TFTs exhibit typical n-type enhancement-mode transfer characteristics but a gate-voltage-dependent, unreliable threshold voltage. We posit that this obscure threshold voltage is attributed to the [...] Read more.
In this paper, we present a threshold-voltage extraction method for zinc oxide (ZnO) thin-film transistors (TFTs). Bottom-gate atomic-layer-deposited ZnO TFTs exhibit typical n-type enhancement-mode transfer characteristics but a gate-voltage-dependent, unreliable threshold voltage. We posit that this obscure threshold voltage is attributed to the localized trap states of ZnO TFTs, of which the field-effect mobility can be expressed as a gate-bias-dependent power law. Hence, we derived the current–voltage relationship by dividing the drain current with the transconductance to rule out the gate-bias-dependent factors and successfully extract the reliable threshold voltage. Furthermore, we investigated the temperature-dependent characteristics of the ZnO TFTs to validate that the observed threshold voltage was genuine. Notably, the required activation energies from the low-temperature measurements displayed an abrupt decrease at the threshold voltage, which was attributed to the conduction route change from diffusion to drift. Thus, we conclude that the reliable threshold voltage of accumulation-mode ZnO TFTs can be determined using a gate-bias-dependent factor-removed current–voltage relationship with a low-temperature analysis. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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11 pages, 3308 KiB  
Article
Physicochemical Properties of Organic Molecular Ferroelectric Diisopropylammonium Chloride Thin Films
by Ahmad M. Alsaad, Qais M. Al-Bataineh, Issam A. Qattan, Ihsan A. Aljarrah, Areen A. Bani-Salameh, Ahmad A. Ahmad, Borhan A. Albiss, Ahmad Telfah and Renat F. Sabirianov
Nanomaterials 2023, 13(7), 1200; https://doi.org/10.3390/nano13071200 - 28 Mar 2023
Viewed by 1350
Abstract
We fabricated ferroelectric films of the organic molecular diisopropylammonium chloride (DIPAC) using the dip-coating technique and characterized their properties using various methods. Fourier-transform infrared, scanning electron microscopy, and X-ray diffraction analysis revealed the structural features of the films. We also performed ab-initio calculations [...] Read more.
We fabricated ferroelectric films of the organic molecular diisopropylammonium chloride (DIPAC) using the dip-coating technique and characterized their properties using various methods. Fourier-transform infrared, scanning electron microscopy, and X-ray diffraction analysis revealed the structural features of the films. We also performed ab-initio calculations to investigate the electronic and polar properties of the DIPAC crystal, which were found to be consistent with the experimental results. In particular, the optical band gap of the DIPAC crystal was estimated to be around 4.5 eV from the band structure total density-of-states obtained by HSE06 hybrid functional methods, in good agreement with the value derived from the Tauc plot analysis (4.05 ± 0.16 eV). The films displayed an island-like morphology on the surface and showed increasing electrical conductivity with temperature, with a calculated thermal activation energy of 2.24 ± 0.03 eV. Our findings suggest that DIPAC films could be a promising alternative to lead-based perovskites for various applications such as piezoelectric devices, optoelectronics, sensors, data storage, and microelectromechanical systems. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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9 pages, 2939 KiB  
Article
Ion-Induced Lateral Damage in the Focused Ion Beam Patterning of Topological Insulator Bi2Se3 Thin Films
by Rubén Gracia-Abad, Soraya Sangiao, Sandeep Kumar Chaluvadi, Pasquale Orgiani and José María De Teresa
Materials 2023, 16(6), 2244; https://doi.org/10.3390/ma16062244 - 10 Mar 2023
Cited by 1 | Viewed by 1205
Abstract
Focused Ion Beam patterning has become a widely applied technique in the last few decades in the micro- and nanofabrication of quantum materials, representing an important advantage in terms of resolution and versatility. However, ion irradiation can trigger undesired effects on the target [...] Read more.
Focused Ion Beam patterning has become a widely applied technique in the last few decades in the micro- and nanofabrication of quantum materials, representing an important advantage in terms of resolution and versatility. However, ion irradiation can trigger undesired effects on the target material, most of them related to the damage created by the impinging ions that can severely affect the crystallinity of the sample, compromising the application of Focused Ion Beam to the fabrication of micro- and nanosized systems. We focus here on the case of Bi2Se3, a topological material whose unique properties rely on its crystallinity. In order to study the effects of ion irradiation on the structure of Bi2Se3, we irradiated with Ga+ ions the full width of Hall-bar devices made from thin films of this material, with the purpose of inducing changes in the electrical resistance and characterizing the damage created during the process. The results indicate that a relatively high ion dose is necessary to introduce significant changes in the conduction. This ion dose creates medium-range lateral damage in the structure, manifested through the formation of an amorphous region that can extend laterally up to few hundreds of nanometers beyond the irradiated area. This amorphous material is no longer expected to behave as intrinsic Bi2Se3, indicating a spatial limitation for the devices fabricated through this technique. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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15 pages, 4789 KiB  
Article
Plasma-Assisted Atomic Layer Deposition of IrO2 for Neuroelectronics
by Valerio Di Palma, Andrea Pianalto, Michele Perego, Graziella Tallarida, Davide Codegoni and Marco Fanciulli
Nanomaterials 2023, 13(6), 976; https://doi.org/10.3390/nano13060976 - 08 Mar 2023
Cited by 1 | Viewed by 1421
Abstract
In vitro and in vivo stimulation and recording of neuron action potential is currently achieved with microelectrode arrays, either in planar or 3D geometries, adopting different materials and strategies. IrO2 is a conductive oxide known for its excellent biocompatibility, good adhesion on [...] Read more.
In vitro and in vivo stimulation and recording of neuron action potential is currently achieved with microelectrode arrays, either in planar or 3D geometries, adopting different materials and strategies. IrO2 is a conductive oxide known for its excellent biocompatibility, good adhesion on different substrates, and charge injection capabilities higher than noble metals. Atomic layer deposition (ALD) allows excellent conformal growth, which can be exploited on 3D nanoelectrode arrays. In this work, we disclose the growth of nanocrystalline rutile IrO2 at T = 150 °C adopting a new plasma-assisted ALD (PA-ALD) process. The morphological, structural, physical, chemical, and electrochemical properties of the IrO2 thin films are reported. To the best of our knowledge, the electrochemical characterization of the electrode/electrolyte interface in terms of charge injection capacity, charge storage capacity, and double-layer capacitance for IrO2 grown by PA-ALD was not reported yet. IrO2 grown on PtSi reveals a double-layer capacitance (Cdl) above 300 µF∙cm−2, and a charge injection capacity of 0.22 ± 0.01 mC∙cm−2 for an electrode of 1.0 cm2, confirming IrO2 grown by PA-ALD as an excellent material for neuroelectronic applications. Full article
(This article belongs to the Topic Advances in Functional Thin Films)
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