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Graphene

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Bandgap Engineering Of 2d Materials And Its Electric And Optical Properties, Kumar Vishal Jan 2023

Bandgap Engineering Of 2d Materials And Its Electric And Optical Properties, Kumar Vishal

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Since their invention in 1958, Integrated Circuits (ICs) have become increasingly more complex, sophisticated, and useful. As a result, they have worked their way into every aspect of our lives, for example: personal electronic devices, wearable electronics, biomedical sensors, autonomous driving cars, military and defense applications, and artificial intelligence, to name some areas of applications. These examples represent both collectively, and sometimes individually, multi-trillion-dollar markets. However, further development of ICs has been predicted to encounter a performance bottleneck as the mainstream silicon industry, approaches its physical limits. The state-of-the-art of today’s ICs technology will be soon below 3nm. At such …


Exploring Two-Dimensional Graphene And Silicene In Digital And Rf Applications, Zhonghang Ji Jan 2019

Exploring Two-Dimensional Graphene And Silicene In Digital And Rf Applications, Zhonghang Ji

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Since the discovery of graphene, two-dimensional (2D) materials have attracted intensive interests in the past 15 years and there has been a growing interest in exploring new materials beyond graphene, such as silicene, germanene, etc. Numerous papers have been published to demonstrate their extraordinary electronic, optical, biological, and thermal properties which render broad applications in various fields. However, the absence of band gap in graphene and silicene prohibits their uses in digital applications. This dissertation reviews recent progress on band gap opening based on mono- and bi- layer silicene and presents a new silicon atomic structure which exhibits a 0.17 …


A Graphene/Rf Gas Sensor, Kathleen Louise Brockdorf Jan 2019

A Graphene/Rf Gas Sensor, Kathleen Louise Brockdorf

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Toxic chemicals have been used as chemical warfare agents since ancient times, but World War 1 saw the beginning of modern chemical proliferation. There are many methods of detecting these agents, but the combination of high sensitivity, specificity, fast response, and small form factor is difficult to achieve. More recently, graphene has been identified as a possible sensing material for ammonia and other substances. This research documents a novel method of using graphene as a chemical sensor, utilizing a radio-frequency approach to sensing. This approach utilizes all available information from the material, such as permittivity and conductivity, instead of simply …


Thermoelectric Transport And Energy Conversion Using Novel 2d Materials, Luke J. Wirth Jan 2016

Thermoelectric Transport And Energy Conversion Using Novel 2d Materials, Luke J. Wirth

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Nanomaterials hold great promise for applications in thermal management and thermoelectric power generation. Defects in these are important as they are generally inevitably introduced during fabrication or intentionally engineered to control the properties of the nanomaterials. Here, we investigate how phonon-contributed thermal conductance in narrow graphene, boron nitride (BN), and silicene nanoribbons (NRs), responds to the presence of a vacancy defect and the corresponding geometric distortion, from first principles using the non-equilibrium Green's function method. Analyses are made of the geometries, phonon conductance coefficients, and local densities of states (LDOS) of pristine and defected nanoribbons. It is found that hydrogen …


Synthesis And Characterization Of Graphene Oxide/Sulfur Nanocomposite For Lithium-Ion Batteries, Aaron Joseph Blake Jan 2013

Synthesis And Characterization Of Graphene Oxide/Sulfur Nanocomposite For Lithium-Ion Batteries, Aaron Joseph Blake

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The growing need for clean and efficient energy storage systems has recently peaked due to concerns of climate change and increased global energy consumption. However, efficiently integrating renewable resources such as solar and wind energy into society will require a complex electrical energy storage (EES) system capable of storing and expending significant amounts of energy. A battery based on the lithium/sulfur couple can yield a theoretical specific energy of 2600Wh/kg, which is about five times higher than that offered by present Li-ion batteries, and hence, is a promising and attractive technology. Despite recent developments in addressing various issues inherent to …


Structural And Electronic Properties Of Two-Dimensional Silicene, Graphene, And Related Structures, Ruiping Zhou Jan 2012

Structural And Electronic Properties Of Two-Dimensional Silicene, Graphene, And Related Structures, Ruiping Zhou

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Traditional CMOS (complementary metal-oxide-semiconductor) transistors have already been in the nanometer range. As bulk silicon material is approaching its physical limits, it is highly desirable to seek novel, functional materials to continue Moore's law. Two-dimensional(2D) materials, such as graphene and silicene, have attracted great attention since they were envisioned a few years ago, having extraordinary electrical properties. Research in this work was focused on understanding the structural and electronic properties of a few atomic layers of carbon (graphene) and silicon (silicene). Atomic structures of the 2D materials, corresponding band structures, and transport properties were calculated based on density functional theory. …


Graphene Based Rf/Microwave Impedance Sensing And Low Loss Conductor For Rf Applications, Iramnaaz Iramnaaz Jan 2011

Graphene Based Rf/Microwave Impedance Sensing And Low Loss Conductor For Rf Applications, Iramnaaz Iramnaaz

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Biosensors are becoming more popular recently and expanding due to their broad applications in detecting disease and infectious agents, monitoring of environmental toxins, etc. Recognition and quantification of biochemical molecules and molecular interactions present great challenges in biosensing [38]. Impedance sensing at radio frequency (RF) /microwave frequency becomes very attractive as bio-molecules exhibits large distinct dielectric properties, and also because the ionic conductivity of water in most physiological systems is greatly diminished. For example, it has been reported that tumoral cells exhibits large value of electrical conductivity and permittivity which can result in significant variation of the impedance when compared …