This thesis presents models for a graphene based field effect transistor (GFET). The graphene material has been widely studied since its synthesis in 2004 and the material holds promise for the next generation electronic applications. Therefore, there is a need to model its device characteristics.In this respect the contributions presented here are, firstly, a SPICE-compatible model for both dual gate and single gate graphene transistors. The derivation of the carrier transport of both hole and electron conduction results in a set of analytical equations. These derivations cover the three identified regions of operation as well as the boundary voltage conditions that define the regions. The Jacobian entries are shown to be continuous across the region boundaries.Secondly, circuit levels model of a single-layer GFET and multi layer GFET suitable for a direct implementation in SPICE. In this contribution, a more accurate threshold voltage compared to other models is derived. This contribution also shows how models can be extended to as many layers the graphene channelled transistor has.Finally, the introduction of a thermionic resistance, which is modelled in parallel with the resistance due to gate induced charges, provides a model for the temperature dependent channel resistance. The contribution goes further to derive equations between the off current and the vertical electric fields. Thus, giving a good estimation of the tunable bandgap opening in graphene.The models in this contributions are validated against experimentally measured transistor characteristics which have been carried out by other research groups and the models show a good agreement in all cases validated. The thesis equally presents the use of a floating gate to optimize the transistors characteristics. To illustrate these contributions, algorithms of the models have been implemented on the following CAD tools, HSPICE, VHDL-AMS and Berkeley SPICE. During the course of this work one journal and five conference papers have been published

Researchers are nowadays trying to develop the materials which are having better properties than the existing one. Graphene has attracted the whole scientific world towards it due to its magnificent mechanical, thermal and electrical properties. These properties allow it to fit in a wide number of applications. These properties are equally significant not only in the field of engineering but also in the field of biomedical. Graphene is a two dimensional sp2 hybridized hexagonally packed allotrope of the carbon. In this review paper, we will discuss the whole information about the Graphene. Along with the historical background and basic introduction, this paper glances through the synthesis methods, extraordinary properties as well as the applications of Graphene. This research work is a collective study of the mentioned criterion of the Graphene to outline its important aspects. How to cite this article: Husainy ASN, Dayma RS, Bapat SS et al. A State of the Art: Graphene Research with their Properties and Applications. J Adv Res Mfg Mater Sci Met Engg 2020; 7(3): 1-10. DOI: https://doi.org/10.24321/2393.8315.202003

Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. The polymers are one of the most commonly used matrices of choice for composites and have found applications in numerous fields. The stiff and fragile structure of monolithic polymers leads to the innate cracks to cause fracture and therefore the engineering applications of monolithic polymers, requiring robust damage tolerance and high fracture toughness, are not ubiquitous. In addition, when “many-parts” cling together to form polymers, a labyrinth of molecules results, which does not offer to electrons and phonons a smooth and continuous passageway. Therefore, the monolithic polymers are bad conductors of heat and electricity. However, it is well established that when polymers are embedded with suitable entities especially nano-fillers, such as metallic oxides, clays, carbon nanotubes, and other carbonaceous materials, their performance is propitiously improved. Among various additives, graphene has recently been employed as nano-filler to enhance mechanical, thermal, electrical, and functional properties of polymers. In this review, advances in the modeling and simulation of grapheme based polymer nanocomposites will be discussed in terms of graphene structure, topographical features, interfacial interactions, dispersion state, aspect ratio, weight fraction, and trade-off between variables and overall performance

Abstract Among various 2D materials, graphene has received extensive research attention in the last 2-3 decades due to its fascinating properties. The discovery of graphene provided an immense boost up and new dimension to materials research and nanotechnology. The multidisciplinary characteristics of graphene havea wide range of applications from health to aerospace. Modern graphene research has been directed towards the exploration of new graphene derivatives and their utilisations for fabrication of products and devices. The enhancement of graphene properties by functionalization or surface modification is another innovative approach. However, like other 2D materials, graphene research also needs amendments and up-gradation in the light of recent scientific output. In this contribution, we have reassessed the recent research output on graphene and graphene-based materials for applications in different fields. For the reader's comfort and to maintain lucidity, first, some fundamental aspects of graphene are discussed and then recent overviews in graphene research are explored in a systematic manner. Overall, this review article provides an outline of graphene in terms of fundamental properties, cutting-edge research and applications.

Owing to its extraordinary electrical, optical, and mechanical properties, graphene has emerged as a promising material for a variety of applications in the future. However, not all these applications will be able to employ or require pristine graphene; hence several alternative methods have developed for the mass production of graphene and related materials. Graphene oxide (GO), a material closely related to graphene, allows engineering of its chemical composition by means of chemical, thermal, and electrochemical methods. This provides an opportunity to tune physical and chemical properties of graphene. This work reports on investigations of the structure of chemically modified graphenes (CMGs) derived from GO, interactions of metals and organic thin films with CMG, and application of metal-CMG as a hydrogen gas sensor. GO was fabricated by a modified Hummers method. GO, being insulating, was reduced by hydrazine and thermal annealing to produce reduced graphene oxide (rGO). The CMG sheets were deposited on TEM grids and on Si/SiO2 substrates for characterization by atomic force microscopy, transmission electron microscopy (TEM), xray photoelectron spectroscopy, and Raman spectroscopy. The structural analysis of GO performed by TEM revealed that in GO, on average, the underlying carbon lattice maintains the symmetry and lattice-spacings of graphene. Compositional analysis disclosed that the as-produced GO is actually made of oxidized graphene like sheets strongly attached with oxidative debris that make the as produced GO hydrophilic and insulating. In the TEM, both GO and reduced GO (rGO) were nearly transparent and stable under the electron beam and hence they made excellent supports to study the growth of thin organic and metal films deposited by physical vapour deposition. The study revealed the interactions of organic molecules, fluorinated copper phthalocyanine, with CMG and packing of the molecules in the crystal structure. Film-thicknesses from sub-monolayer to tens of monolayers were analysed. In the study of metal thin film growth, the factors determining the growth and morphology of different metals-on-CMG were studied. Fine control over the size and coverage of nanoparticles were achieved. This control was used to combine Pd nanoparticles and rGO to design selective, highly sensitive, and practical hydrogen gas sensor

Porous graphene, including 2D and 3D porous graphene, is widely researched recently. One of the most attractive features is the proper utilization of graphene defects, which combine the advantages of both graphene and porous materials, greatly enriching the applications of porous graphene in biology, chemistry, electronics, and other fields. In this review, the defects of graphene are first discussed to provide a comprehensive understanding of porous graphene. Then, the latest advancements in the preparation of 2D and 3D porous graphene are presented. The pros and cons of these preparation methods are discussed in detail, providing a direction for the fabrication of porous graphene. Moreover, various superior properties of porous graphene are described, laying the foundation for their promising applications. Owing to its abundant morphology, wide distribution of pore size, and remarkable properties benefited from porous structure, porous graphene can not only promote molecular diffusion and electron transfer but also expose more active sites. Consequently, a serious of applications containing gas sieving, liquid separation, sensors, and supercapacitors, are presented. Finally, the challenges confronted during preparation and characterization of porous graphene are discussed, offering guidance for the future development of porous graphene in fabrication, characterization, properties, and applications.

Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. Due to the hexagonal structure of graphene, it is considered as frame-like structure. In the frame, covalent C-C bonds are taken as beams joined together with carbon atoms placed at the joints. Uniaxial beam elements, defined by their cross-sectional area, material properties, and moment of inertia represent the covalent bonds. The parameters of the beam elements are determined by establishing equivalence between structural and computational mechanics. However, the bonds connecting the carbon atoms do not have physical existence as they are a compromise between attractive and repulsive forces. Also, defects at nanoscale make graphene different from frame-like structure. In addition, the topography of graphene makes it non-linear structure and even the axial loading changes to eccentric loading. Here we show that, by using basic statics principles, disparities between graphene and frame-likes structures can be highlighted

The growing presence of diverse pollutants, including heavy metals, organic compounds, pharmaceuticals, and emerging contaminants, poses significant environmental and health risks. Traditional methods for pollutant removal often face limitations in efficiency, selectivity, and sustainability. This review provides a comprehensive analysis of recent advancements in innovative adsorbents designed to address these challenges. It explores a wide array of non-conventional adsorbent materials, such as nanocellulose, metal–organic frameworks (MOFs), graphene-based composites, and biochar, emphasizing their sources, structural characteristics, and unique adsorption mechanisms. The review discusses adsorption processes, including the basic principles, kinetics, isotherms, and the factors influencing adsorption efficiency. It highlights the superior performance of these materials in removing specific pollutants across various environmental settings. The practical applications of these adsorbents are further explored through case studies in industrial settings, pilot studies, and field trials, showcasing their real-world effectiveness. Additionally, the review critically examines the economic considerations, technical challenges, and environmental impacts associated with these adsorbents, offering a balanced perspective on their viability and sustainability. The conclusion emphasizes future research directions, focusing on the development of scalable production methods, enhanced material stability, and sustainable regeneration techniques. This comprehensive assessment underscores the transformative potential of innovative adsorbents in pollutant remediation and their critical role in advancing environmental protection.

The properties of graphene nanoribbons are dependent on both the nanoribbon width and the crystallographic orientation of the edges. Scanning tunneling microscope lithography is a method which is able to create graphene nanoribbons with well defined edge orientation, having a width of a few nanometers. However, it has only been demonstrated on the top layer of graphite. In order to allow practical applications of this powerful lithography technique, it needs to be implemented on single layer graphene. We demonstrate the preparation of graphene nanoribbons with well defined crystallographic orientation on top of gold substrates. Our transfer and lithography approach brings one step closer the preparation of well defined graphene nanoribbons on arbitrary substrates for nanoelectronic applications

This thorough review explores the pioneering applications of graphene oxide (GO) in tackling emerging environmental pollutants, highlighting its distinct role in environmental remediation. Setting itself apart, this review meticulously synthesizes cutting-edge research, focusing on GO’s practical applications in eliminating emerging contaminants from water. It is worth highlighting that there is a limited number of reviews focused on this particular subject, making this work outstanding. It provides specific instances of successful contaminant removal, identifies knowledge gaps, and proposes future directions. Serving as a vital resource for researchers and practitioners, it offers practical insights into applying GO in contaminant remediation, especially in challenging environments. The review critically analyzes crucial gaps in current research, including understanding the long-term environmental effects of GO, its interactions with diverse pollutants, and effective large-scale implementation. This review not only expands our knowledge, but also guides future research endeavors. Furthermore, it outlines clear pathways for future studies, advocating for in-depth ecological research, advanced contaminant interaction analyses, and innovative large-scale implementation strategies. This work establishes a strong foundation, defining the unique novelty of GO applications in environmental remediation and shaping the future discourse in this essential field of study.

The use of graphene nanocomposites in advanced applications has attracted much attention in recent years. However, in order to substitute traditional epoxy reinforcements with graphene, there are still some issues like dispersion, homogenization, and reaggregation. In this paper, graphene bundles dispersed in two-component epoxy system by bath sonication, dispersion state, and reaggregation behavior of graphene in this system have been studied. Light transmittance in ultraviolet-visible spectroscopy has been used to quantify the reaggregation by a series of controlled experiments. After 18 mins sonication of 0.005 wt% graphene dispersion at 20°C, the light transmittance decreased from 68.92% to 54.88% in liquid epoxy and decreased from 72.80% to 46.42% in hardener; while increasing the temperature from 20°C to 60°C, the light transmittance in liquid epoxy decreased from 65.96% to 53.21% after 6 mins sonication. With the incorporation of 0.3 wt% graphene, the tensile strength of nanocomposites increased from 57.2 MPa to 64.4 MPa and the storage modulus increased from 1.66 GPa to 2.16 GPa. The results showed that the dispersion state depends on the function of sonication time and temperature, and graphene has a significant reinforcement effect on epoxy

Graphene has been regarded as a potential application material in the field of new energy conversion and storage because of its unique two-dimensional structure and excellent physical and chemical properties. However, traditional graphene preparation methods are complicated in-process and difficult to form patterned structures. In recent years, laser-induced graphene (LIG) technology has received a large amount of attention from scholars and has a wide range of applications in supercapacitors, batteries, sensors, air filters, water treatment, etc. In this paper, we summarized a variety of preparation methods for graphene. The effects of laser processing parameters, laser type, precursor materials, and process atmosphere on the properties of the prepared LIG were reviewed. Then, two strategies for large-scale production of LIG were briefly described. We also discussed the wide applications of LIG in the fields of signal sensing, environmental protection, and energy storage. Finally, we briefly outlined the future trends of this research direction.

The quest for materials capable of realizing the next generation of electronic and photonic devices continues to fuel research on the electronic, optical and vibrational properties of graphene. Few-layer graphene (FLG) flakes with less than ten layers each show a distinctive band structure. Thus, there is an increasing interest in the physics and applications of FLGs. Raman spectroscopy is one of the most useful and versatile tools to probe graphene samples. Here, we uncover the interlayer shear mode of FLGs, ranging from bilayer graphene (BLG) to bulk graphite, and suggest that the corresponding Raman peak measures the interlayer coupling. This peak scales from ~43 cm−1 in bulk graphite to ~31 cm−1 in BLG. Its low energy makes it sensitive to near-Dirac point quasiparticles. Similar shear modes are expected in all layered materials, providing a direct probe of interlayer interactions

Graphene is an emerging nanomaterial increasingly being used in electrochemical biosensing applications owing to its high surface area, excellent conductivity, ease of functionalization, and superior electrocatalytic properties compared to other carbon-based electrodes and nanomaterials, enabling faster electron transfer kinetics and higher sensitivity. Graphene electrochemical biosensors may have the potential to enable the rapid, sensitive, and low-cost detection of cancer biomarkers. This paper reviews early-stage research and proof-of-concept studies on the development of graphene electrochemical biosensors for potential future cancer diagnostic applications. Various graphene synthesis methods are outlined along with common functionalization approaches using polymers, biomolecules, nanomaterials, and synthetic chemistry to facilitate the immobilization of recognition elements and improve performance. Major sensor configurations including graphene field-effect transistors, graphene modified electrodes and nanocomposites, and 3D graphene networks are highlighted along with their principles of operation, advantages, and biosensing capabilities. Strategies for the immobilization of biorecognition elements like antibodies, aptamers, peptides, and DNA/RNA probes onto graphene platforms to impart target specificity are summarized. The use of nanomaterial labels, hybrid nanocomposites with graphene, and chemical modification for signal enhancement are also discussed. Examples are provided to illustrate applications for the sensitive electrochemical detection of a broad range of cancer biomarkers including proteins, circulating tumor cells, DNA mutations, non-coding RNAs like miRNA, metabolites, and glycoproteins. Current challenges and future opportunities are elucidated to guide ongoing efforts towards transitioning graphene biosensors from promising research lab tools into mainstream clinical practice. Continued research addressing issues with reproducibility, stability, selectivity, integration, clinical validation, and regulatory approval could enable wider adoption. Overall, graphene electrochemical biosensors present powerful and versatile platforms for cancer diagnosis at the point of care.

Graphene growth by low-pressure chemical vapor deposition on low cost copper foils shows great promise for large scale applications. It is known that the local crystallography of the foil influences the graphene growth rate. Here we find an epitaxial relationship between graphene and copper foil. Interfacial restructuring between graphene and copper drives the formation of (n10) facets on what is otherwise a mostly Cu(100) surface, and the facets in turn influence the graphene orientations from the onset of growth. Angle resolved photoemission shows that the electronic structure of the graphene is decoupled from the copper indicating a weak interaction between them. Despite this, two preferred orientations of graphene are found, ±8° from the Cu[010] direction, creating a non-uniform distribution of graphene grain boundary misorientation angles. Comparison with the model system of graphene growth on single crystal Cu(110) indicates that this orientational alignment is due to mismatch epitaxy. Despite the differences in symmetry the orientation of the graphene is defined by that of the copper. We expect these observations to not only have importance for controlling and understanding the growth process for graphene on copper, but also to have wider implications for the growth of two-dimensional materials on low cost metal substrates

In recent years, the pursuit of high-performance nano-flexible electronic composites has led researchers to focus on nanocellulose-graphene composites. Nanocellulose has garnered widespread interest due to its exceptional properties and unique structure, such as renewability, biodegradability, and biocompatibility. However, nanocellulose materials are deficient in electrical conductivity, which limits their applications in flexible electronics. On the other hand, graphene boasts remarkable properties, including a high specific surface area, robust mechanical strength, and high electrical conductivity, making it a promising carbon-based nanomaterial. Consequently, research efforts have intensified in exploring the preparation of graphene-nanocellulose flexible electronic composites. Although there have been studies on the application of nanocellulose and graphene, there is still a lack of comprehensive information on the application of nanocellulose/graphene in flexible electronic composites. This review examines the recent developments in nanocellulose/graphene flexible electronic composites and their applications. In this review, the preparation of nanocellulose/graphene flexible electronic composites from three aspects: composite films, aerogels, and hydrogels are first introduced. Next, the recent applications of nanocellulose/graphene flexible electronic composites were summarized including sensors, supercapacitors, and electromagnetic shielding. Finally, the challenges and future directions in this emerging field was discussed.

Graphene has recently attracted significant academic and industrial interest because of its excellent performance in mechanical, electrical and thermal applications. Graphene can significantly improve physical properties of epoxy at extremely small loading when incorporated appropriately. Herein, the structure, preparation and properties of epoxy/graphene nanocomposites are reviewed in general, along with detailed examples drawn from the key scientific literature. The modification of graphene and the utilization of these materials in the fabrication of nanocomposites with different processing methods have been explored. This review has been focused on the processing methods and mechanical, electrical, thermal, and fire retardant properties of the nanocomposites. The synergic effects of graphene and other fillers in epoxy matrix have been summarised as well

Abstract Purpose This study aims to reveal the landscape and trends of graphene research in the world by using data from Chemical Abstracts Service (CAS). Design/methodology/approach Index data from CAS have been retrieved on 78,756 papers and 23,057 patents on graphene from 1985 to March 2016, and scientometric methods were used to analyze the growth and distribution of R&D output, topic distribution and evolution, and distribution and evolution of substance properties and roles. Findings In recent years R&D in graphene keeps in rapid growth, while China, South Korea and United States are the largest producers in research but China is relatively weak in patent applications in other countries. Research topics in graphene are continuously expanding from mechanical, material, and electrical properties to a diverse range of application areas such as batteries, capacitors, semiconductors, and sensors devices. The roles of emerging substances are increasing in Preparation and Biological Study. More techniques have been included to improve the preparation processes and applications of graphene in various fields. Research limitations Only data from CAS is used and some R&D activities solely reported through other channels may be missed. Also more detailed analysis need to be done to reveal the impact of research on development or vice verse, development dynamics among the players, and impact of emerging terms or substance roles on research and technology development. Practical implications This will provide a valuable reference for scientists and developers, R&D managers, R&D policy makers, industrial and business investers to understand the landscape and trends of graphene research. Its methodologies can be applied to other fields or with data from other similar sources. Originality/value The integrative use of indexing data on papers and patents of CAS and the systematic exploration of the distribution trends in output, topics, substance roles are distinctive and insightful.