Papers by Mariana Amorim Fraga
J. Aerosp. Technol. Manag, 2024
This review article provides a concise view of the transformative role played by silicon carbide ... more This review article provides a concise view of the transformative role played by silicon carbide (SiC) semiconductors in the electric power industry, along with a description of their emerging applications in electric vehicles (EVs), renewable energy systems, aeronautics, and space. It highlights SiC chips' ability to operate at high temperatures and frequencies, surpassing the limitations of traditional silicon chips and resulting in enhanced efficiency. Additionally, it also presents the capabilities of SiC devices to manage elevated power levels within reduced size and weight parameters, emphasizing their impact on augmenting power density in EVs and enhancing reliability and efficiency in renewable energy, aeronautics, and space applications. Finally, the review concludes by providing an overview of the prevailing trends, existing challenges, and the future trajectory of SiC semiconductors within these important sectors.
Materials Science Forum, 2006
The aim of this contribution was to evaluate the synthesis of perovskites containing cerium by th... more The aim of this contribution was to evaluate the synthesis of perovskites containing cerium by the combustion synthesis methodology as well as their catalytic behaviour in the methane combustion. Cerium was introduced partially replacing lanthanum into A position of perovskites with general formula AxA’1-xCoO3. The formation of cubic perovskites was confirmed by XRD. The powder containing only lanthanum and strontium in A sites showed a structure transition to orthorhombic at temperatures above 700 °C. The addition of cerium, instead of strontium, induced a structural stabilisation and only a cubic phase was detected up to 1100 °C. High cerium loadings led to the formation of cerium oxide, revealing its up limit into the structure. All samples showed to be active in methane combustion. The results indicated that over the perovskites loaded with cerium the oxygen adsorbed onto the catalyst surface plays a role in the reaction.
Coatings, May 7, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Communications in computer and information science, Dec 31, 2022
Flexible photovoltaic panels, also known as thin-film solar panels, have gained attention in rece... more Flexible photovoltaic panels, also known as thin-film solar panels, have gained attention in recent years due to their unique characteristics and potential applications in emerging fields such as wearable technology. This article reports an experimental study with the aim of analyzing the static and dynamic electrical behavior of three types of flexible photovoltaic panels, namely amorphous silicon (a-Si), copper indium gallium diselenide (CIGS) and organic photovoltaic (OPV). The dynamic measurements were performed using a two-axis solar tracker. The prototype of solar tracker was carefully designed, including the design of the 3D model of the parts of the system and the electronic circuit, created in the Tinkercad software. The tracker logic was implemented using the C + + language, resulting in a simple but functional code to maximize the solar trajectory. The static and dynamic electrical results obtained provide a comprehensive view of the performance of the flexible photovoltaic panels and can help to optimize their use.
(Nano)-materials for Biomedical Applications Issue date: June 2019 Submission deadline: November ... more (Nano)-materials for Biomedical Applications Issue date: June 2019 Submission deadline: November 1, 2018Nanotechnology has been responsible for an unprecedented positive impact in healthcare advances, by merging fundamental and applied sciences as complementary tools envisioning an enhanced quality of life. Recently, a broader spectrum of high performance nanomaterials and material-based nanosystems has been engineered to address challenges in medical and health-related fields. At the same time, there has been a shift in importance from designing exclusively bioinert materials to instead producing complex bioactive building blocks for mimicking targeted functions. This JMR Focus Issue is devoted to the latest advances in biomedical nanomaterials, including: (i) different fabrication approaches and applications, (ii) design and characterization of novel biomedical materials and devices as well as their structure-property relationships with biological responses, and (iii) novel (bio)-nanomaterials as potential candidates to integrate multifunctional devices targeting self-assembly materials.https://www.cambridge.org/core/journals/journal-of-materials-research/information/jmr-focus-issues/call-for-papers-nano-materials-for-biomedical-applications?utm_source=Web Graphic&utm_medium=Cambridge Core&utm_campaign=JMR - CFP Nano Materials
Carbon-based films as piezoresistive material
Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atrib... more Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atribuição 4.0 Internacional (CC BY 4.0). O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.
Materials Science Forum, Mar 1, 2011
This work compares the piezoresistive properties of SiC thin films produced by two techniques enh... more This work compares the piezoresistive properties of SiC thin films produced by two techniques enhanced by plasma, PECVD (plasma enhanced chemical vapor deposition) and RF magnetron sputtering. In order to study these properties, strain gauges based on SiC films produced were fabricated using photolithography techniques in conjunction with lift-off processes. The beam-bending method was used to characterize the SiC strain gauges fabricated.
Materials, Oct 22, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Different substrate surface pretreatments have been used to improve the adhesion of CVD diamond c... more Different substrate surface pretreatments have been used to improve the adhesion of CVD diamond coatings on WC-Co substrates. This paper reports the results of a pretreatment method based on two-step chemical etching: first in Murakami solution and then in aqua regia. A systematic study was performed to evaluate the influence of the pretreatment on the composition and morphology of the WC-Co substrate. Furthermore, the effect of diamond nanoparticle seeding on the morphology and roughness of the substrate was also investigated. After these studies, diamond coating was deposited on seeded WC-Co substrate by hot-filament CVD. The sample was characterized by Raman spectroscopy, FEG-SEM and AFM. Rockwell C indentation test was used to evaluate the adhesion between the CVD diamond coating and the WC-Co substrate.
Revista brasileira de aplicações de vácuo, Apr 30, 2016
Different substrate surface pretreatments have been used to improve the adhesion of CVD diamond c... more Different substrate surface pretreatments have been used to improve the adhesion of CVD diamond coatings on WC-Co substrates. This paper reports the results of a pretreatment method based on two-step chemical etching: first in Murakami solution and then in aqua regia. A systematic study was performed to evaluate the influence of the pretreatment on the composition and morphology of the WC-Co substrate. Furthermore, the effect of diamond nanoparticle seeding on the morphology and roughness of the substrate was also investigated. After these studies, diamond coating was deposited on seeded WC-Co substrate by hot-filament CVD. The sample was characterized by Raman spectroscopy, FEG-SEM and AFM. Rockwell C indentation test was used to evaluate the adhesion between the CVD diamond coating and the WC-Co substrate.
Silicon
Amorphous silicon carbide (a-SiC) films hold promise for microelectronic and MEMS devices. Prior ... more Amorphous silicon carbide (a-SiC) films hold promise for microelectronic and MEMS devices. Prior to their use in microfabricated devices, these films undergo plasma etching. This study investigates reactive ion etching (RIE) of sputtered a-SiC films on Si (100) substrates using sulfur hexafluoride (SF6) gas. The focus is on the impact of RF power on the thickness, structure, chemistry, and morphology of the SiC film. Grazing Incidence X-ray Diffraction (GIXRD) analysis of the etched samples indicates crystalline SiC formation at low temperatures. Surface morphology analysis using Field Emission Scanning Electron Microscopy (FESEM) confirms the GIXRD results. The RIE process unintentionally induces crystallization of a-SiC films, but adjusting etching process parameters allows control over film crystallinity.
Journal of Aerospace Technology and Management, 2019
IEEE Sensors Journal
The demand for innovative and versatile technologies in wearable electronics has catalyzed resear... more The demand for innovative and versatile technologies in wearable electronics has catalyzed research into functional materials that can seamlessly integrate with complex and curved surfaces. Recent advances in sputtering technology have not only enabled precise control over the thin film composition and crystal structure on various substrates, including flexible ones, but have also made it easier to optimize a sensor’s performance for specific applications. Piezoelectric thin films produced by sputtering techniques are recognized for their exceptional electromechanical properties and offer a promising approach for developing low-cost, high-performance flexible sensors. These sensors have a wide range of applications, from wearable devices to environmental monitoring. In this review article, we present and discuss the use of sputtered piezoelectric thin films as materials for flexible devices and sensors. The growth of these thin films through sputtering, their piezoelectric properties, and the sensor fabrication processes are detailed, with a focus on challenges that remain to be addressed. We also discuss the difficulties in optimizing film performance while ensuring mechanical durability, emphasizing the importance of material engineering. Additionally, the broad spectrum of applications for flexible devices and sensors is highlighted.
Elsevier eBooks, 2021
The atomic layer deposition (ALD) is not only an ultrathin film technology used in semiconductor ... more The atomic layer deposition (ALD) is not only an ultrathin film technology used in semiconductor industries. Lately, it has been found in many applications in the renewable energy field due to its precise control of thickness of up to a few angstroms and its unique characteristic of grown conformal and uniform films in any 3D structure of random geometry. ALD has long-range applications in this field, including electrochemical storage, fuel cells, photovoltaic solar energy, and photoelectrochemical (PEC) water splitting to produce hydrogen as a green fuel. In PEC water splitting, ALD is now being extensively used as an efficient tool to deposit surface passivation layers, absorber, and barrier and buffer layers in several kinds of PEC cells. This chapter aims to briefly review PEC technology, as well as to introduce the main ALD-based materials used to improve the solar-to-hydrogen efficiency that help to make this technology commercially viable.
Frontiers in Mechanical Engineering, Oct 28, 2020
Chiappim et al. Crystallinity Quality of TiO 2 ALD there was better stability of the parameters a... more Chiappim et al. Crystallinity Quality of TiO 2 ALD there was better stability of the parameters analyzed for TiCl 4 in the two atomic layer deposition modes.
The wide use of sunlight for energy generation still facing challenges related to high cost and l... more The wide use of sunlight for energy generation still facing challenges related to high cost and low efficiency. The successful expansion of the capacity for solar energy production depends on technological advances in several fields, particularly materials science and engineering. The key mechanisms of solar energy conversion are dominated by the intrinsic properties of the active materials that constitute the photovoltaic or solar thermal collector systems. An intensive research on the synthesis and properties of materials for solar energy conversion, especially nanomaterials, has been carried out in order to build solar systems with lower cost and higher efficiency. Carbon-based nanomaterials have been recognized as promising candidates due to their outstanding physicochemical properties. Among them, metal-containing diamond-like carbon (Me-DLC) coatings have been investigated to enhance absorption of solar radiation and also enhance heat transfer to working fluid in solar collectors. In this chapter, the focus is on the synthesis, properties and solar absorber coating applications of Me-DLC films. The fundamental mechanisms related to selective solar absorbers are described. The main synthesis methods of Me-DLC films are reviewed. Furthermore, the material properties of Me-DLC films are discussed as a function of type of transition metal, such as Cr, W, Ti, Pt, etc., which is incorporated into the DLC film. The promising results reported in literature using Me-DLC films as selective solar absorber coatings are also being discussed.
A highly miniaturized piezoresistive humidity sensor has been developed. The starting point of th... more A highly miniaturized piezoresistive humidity sensor has been developed. The starting point of the development was a 1 × 1 mm 2 piezoresistive pressure sensor chip. As sensing material, a polyimide was used that swells with increasing adsorption of water molecules. To convert the swelling into an electrical signal, a thin layer of the polyimide was deposited onto the bending plate of the pressure sensor. The humidity sensor was characterized in a climate chamber. The measurements show a sensitivity of 0.25 mV per percent relative humidity (%RH) and a non-linearity of 3.1 % full scale (FS) in the range of 30-80 % RH. A high cross-sensitivity to temperature of around 0.5 mV • C −1 was measured, so temperature compensation is necessary. For stress-free packaging of the sensor chip, a novel packaging technology was developed.
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Papers by Mariana Amorim Fraga
The motivation was to control the sputtering rate of each target so as to vary the stoichiometric ratio x/y of the deposited films. The species content, thickness and chemical bonds of
as-deposited SixCy films were studied by Rutherford backscattering spectroscopy (RBS), profilometry, Fourier transform infrared absorption (FTIR) and Raman spectroscopy
respectively. Overall, the present work reveals a new reliable plasma sputtering technique for low temperature growth of amorphous SixCy thin films with the capability of tuning the
degree of formation of a-SiC, a-Si and a-C bonds in the film bulk.
The book concludes with a chapter on theoretical insights for designing sensors, (bio)sensors for medical, food and environmental applications and the future of sensors. This book is suitable for materials scientists and engineers and biomedical engineers in academia or industry.
analysis of piezoresistive graphite sensors in paper substrate and encapsulated with epoxy resin. Graphite in thin paper films have been investigated for a wide range of applications due to their excellent electrical and mechanical properties. The processing of graphite sensor elements using mechanical exfoliation in paper, GoP method, does not generate considerable environmental impacts, does not demand complex processes and equipment that generate high costs and have controllable functionalities. In the last decade, several research and development activities have been conducted on the use of these thin films as piezoresistors in MEMS sensors. The sensor was designed from the analytical formulas found in the literature and the analysis of the results was obtained with the SciDAVis free software. Graphite sensors on flexible polymer substrates can be applied to portable wearable devices, as well as sensors for the Internet of things, bioengineering
and applications in various areas of science and technology.
The book is an important reference for students and researchers (from academics, but also industry) interested in understanding the properties of emerging materials.
size. Understanding the thin films properties and how these properties are affected by synthesis conditions is critical to the successful implementation of solar energy conversion devices. It is imperative that the development of highly efficient conversion devices depends on the proper material selection. Diamond thin films exhibit potentially beneficial characteristics to be employed in photovoltaic and thermionic
devices. They possess a range of superior electronic, optical, mechanical and chemical properties to outclass competing wide-bandgap materials. The combination of these properties offers engineering solutions that can shift performance to new levels
or enable completely new approaches to challenging problems in different applications. This chapter presents an overview on the synthesis and properties of CVD diamond films and on their applications in solar energy conversion. The basic issues and application challenges are discussed.
Book Editors:
Kuan Yew Cheong, Universiti Sains Malaysia, Malaysia
Giuliana Impellizzeri, Italian National Research Council (CNR), Italy
Mariana Amorim Fraga, National Institute for Space Research, Brazil / Universidade Brasil
Guest Editors
Judy Wu, University of Kansas, USA
Mariana Fraga, Federal University of São Paulo, Brazil
Piraviperumal Malar, SRM Institute of Science and Technology, India
Luisa Whittaker-Brooks, University of Utah, USA
Marta Marmiroli, University of Parma, Italy
Maria Vesna Nikolić, University of Belgrade – Institute for Multidisciplinary Research, Serbia
Junying Zhang, Beihang University, China
Scope
Women researchers have made significant contributions to materials science despite long-standing challenges of gender biases and stereotypes. This focus issue on Women's Achievements and Perspectives in Materials Sciences celebrates the achievements of women in the field of material research by collecting outstanding articles of original research works, reviews and perspectives by women scientists around the world. Through highlights of the achievements of women in material research, this focus issue aims to illustrate their broader impact on the advance of science and technology, and the inspiration of next-generation of scientists and engineers in materials researches and other relevant fields.
Materials synthesis
Materials structures
Characterization of materials
Theoretical calculation and simulation of materials
Structure-function relationships in materials for energy and quantum science
Application of nanomaterials to plants and agriculture research
Functionality of materials
Nanoparticles and nanocomposites: synthesis, characterization and application
Submission process
We invite authors to submit original research articles and reviews to this focus collection, which will also feature invited articles. Please submit using our online submission form. All submitted articles are subject to the same review process as regular Materials Research Express articles.
https://iopscience.iop.org/collections/mrx-221230-83
Its scope includes the different classes of functional materials, such as electronic materials, optical materials, sensing materials, biomaterials, among others, of all types (metals, ceramics, polymers and composites) and forms (nanostructures, thin films and bulks). Furthermore, the purpose and scope of study in this field are also to develop materials with excellent mechanical, physical, and chemical properties, in addition to issues related to the application.
https://iopscience.iop.org/journal/2053-1591/page/focus-on-theoretical-and-experimental-advances-in-functional-materials
· Section I. Basic Properties and Types of Semiconducting Polymer Materials
· Section II. Synthesis Methods, Characterization and Processing of Semiconducting Polymer Materials
· Section III. Biosensing Applications of Semiconducting Polymer Materials
· Section IV. Novel Applications and Future Directions for Semiconducting Polymer Materials
https://www.orkg.org/orkg/comparison/R148383
https://www.orkg.org/orkg/comparison/R145556
https://www.orkg.org/orkg/comparison/R144936
https://www.orkg.org/orkg/comparison/R143853
https://www.orkg.org/orkg/comparison/R143716
https://www.orkg.org/orkg/comparison/R141906
https://www.orkg.org/orkg/comparison/R141699
https://www.orkg.org/orkg/comparison/R141156
https://www.orkg.org/orkg/comparison/R139972
https://www.orkg.org/orkg/comparison/R139295
https://www.orkg.org/orkg/comparison/R137472
The book begins by discussing solar energy and photovoltaics, first with a general presentation on solar-energy-conversion principles and semiconductor properties, and subsequently describing solar cells and their efficiency. Chapters 2–5 address the different types of solar cells: crystalline silicon cells, thin-film solar cells, III–V semiconductor solar cells, and organic and polymer solar cells. These chapters explain the synthesis and properties of the materials, operation, efficiency, and applications of each type of solar cell.
The focus of chapter 6 is upon manufacturing technology of the main types of solar cells, such as the baseline processes of crystalline silicon cells and III–V semiconductor-based cell technology. Chapter 7 explains the manufacturing of solar PV modules. The description of the characterization techniques used during SPV module manufacturing continues throughout chapter 8. Chapter 9 introduces SPV systems, covering topics such as solar inverters and power conditioning units, classification of SPV systems, energy production, and the economic viability of these systems. The book concludes with a chapter devoted to the design and implementation of off-grid and on-grid SPV systems.
This book is an excellent choice for an introductory course in PV technology for graduate and undergraduate students. It is also a good reference for scientists and engineers working in this area. Overall, it provides a good overview of fundamental concepts, principles, and applications of photovoltaic devices and systems, including an extensive list of relevant and updated references.