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Full-Text Articles in Physics

Measuring The Double Layer Capacitance Of Electrolyte Solutions Using A Graphene Field Effect Transistor, Agatha Ulibarri May 2018

Measuring The Double Layer Capacitance Of Electrolyte Solutions Using A Graphene Field Effect Transistor, Agatha Ulibarri

Senior Theses

When operating graphene field effect transistors (GFETs) in fluid, a double layer capacitance (Cdl) is formed at the surface. In the literature, the Cdl is estimated using values obtained using metal electrode experiments. Due to the distinctive electronic and surface properties of graphene, there is reason to believe these estimates are inadequate. This work seeks to directly characterize the double layer capacitance of a GFET. A unique method for determining the Cdl has been implemented, and data has been obtained for three electrolytes and one ionic fluid. The results yield dramatically lower Cdl values than those ...


Stacking 2d Materials, Michael Hernandez, John C. Mann Mar 2017

Stacking 2d Materials, Michael Hernandez, John C. Mann

Seaver College Research And Scholarly Achievement Symposium

Monolayer Transition Metal Dichalcogenides are atomically thin semi-conductors that are considered quasi 2D materials due to their extremely small thickness. It has been observed that atomically thin crystals exhibit different physical properties than their bulk counterparts due to quantum confinement effects. We are attempting discover new physical properties by developing a technique to stack two different monolayer crystals, MoS2 and MoSe2.


Epitaxial Growth Of Silicon On Poly-Crystalline Si Seed Layer At Low Temperature By Using Hot Wire Chemical Vapor Deposition, Manal Abdullah Aldawsari May 2015

Epitaxial Growth Of Silicon On Poly-Crystalline Si Seed Layer At Low Temperature By Using Hot Wire Chemical Vapor Deposition, Manal Abdullah Aldawsari

Theses and Dissertations

There has been a growing interest in using low cost material as a substrate for the large grained polycrystalline silicon photovoltaic devices. The main property of those devices is the potential of obtaining high efficiency similar to crystalline Si devices efficiency yet at much lower cost because of the thin film techniques. Epitaxial growth of Si at low temperatures on low cost large grained seed layers, prepared by aluminum induced crystallization method (AIC), using hot wire chemical vapor deposition (HWCVD) system is investigated in this thesis. In this work, different parameters have been studied in order to optimize the growth ...


Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato Nov 2012

Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato

Publications

Europium doped alkaline earth fluoride [Eu:AEF2 (AE = Ca, Sr, Ba)] nanoparticles were synthesized and systematically incorporated into the core of modified chemical vapor deposition (MCVD)-derived silica-based preforms by solution doping. The resulting preforms were examined to determine the impact of the nanoparticles chemistry on the spectroscopic behavior of the glass. The dominant existence of Eu3+ was demonstrated in all preforms, which is in contrast to conventional solution doped preforms employing dissolved europium salts where Eu2+ is primarily observed. Raman spectroscopy and fluorescence lifetime measurements indicated that the nanoparticles composition is effective in controlling, at a local chemical and ...


Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock May 2012

Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock

Theses and Dissertations

Graphene, what some are terming the "new silicon", has the possibility of revolutionizing technology through nanoscale design processes. Fabrication of graphene for device processing is limited largely by the temperatures used in conventional deposition. High temperatures are detrimental to device design where many different materials may be present. For this reason, graphene synthesis at low temperatures using plasma-enhanced chemical vapor deposition is the subject of much research. In this thesis, a tool for ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV-PECVD) and accompanying subsystems, such as control systems and alarms, are designed and implemented to be used in future graphene growths ...


The Density Factor In The Synthesis Of Carbon Nanotube Forest By Injection Chemical Vapor Deposition, Robert W. Call, C. Read, C Mart, T. C. Shen Jan 2012

The Density Factor In The Synthesis Of Carbon Nanotube Forest By Injection Chemical Vapor Deposition, Robert W. Call, C. Read, C Mart, T. C. Shen

Graduate Student Publications

Beneath the seeming straight-forwardness of growing carbon nanotube(CNT) forests by the injection chemical vapor deposition(CVD) method, control of the forest morphology on various substrates is yet to be achieved. Using ferrocene dissolved in xylene as the precursor, we demonstrate that the concentration of ferrocene and the injection rate of the precursor dictate the CNT density of these forests. However, CNT density will also be affected by the substrates and the growth temperature which determine the diffusion of the catalyst adatoms. The CNT growth rate is controlled by the temperature and chemical composition of the gases in the CVD ...


Pore Structure, Barrier Layer Topography And Matrix Alumina Structure Of Porous Anodic Alumina Film, Yucheng Sui, B.Z. Cui, L. Martinez, R. Perez, David J. Sellmyer Apr 2002

Pore Structure, Barrier Layer Topography And Matrix Alumina Structure Of Porous Anodic Alumina Film, Yucheng Sui, B.Z. Cui, L. Martinez, R. Perez, David J. Sellmyer

David Sellmyer Publications

Different anodic voltages and methods were adopted to produce porous anodic alumina films (PAAF) in an aqueous solution of oxalic acid. Carbon tube growth by chemical vapor deposition (CVD) in the films was used to copy the internal pore structure and was recorded by transmission electron microscopy (TEM) photos. Atomic force microscope (AFM) was employed to obtain the topography of the barrier layer of the corresponding films. When the anodic voltage was 40 V and the two-step method adopted, the barrier layer of the film had domains with highly ordered hexagonal cell distribution, and the corresponding pores were straight. When ...


Photoluminescence Study Of Gallium Arsenide, Aluminum Gallium Arsenide, And Gallium Antimonide Thin Films Grown By Metalorganic Chemical Vapor Deposition, John Mark Koons Jan 1994

Photoluminescence Study Of Gallium Arsenide, Aluminum Gallium Arsenide, And Gallium Antimonide Thin Films Grown By Metalorganic Chemical Vapor Deposition, John Mark Koons

Theses

The photoluminescence produced by four MOCVD grown epitaxial thin film samples was studied to give insight into sample quality. The four samples under this study were GaAs on a GaAs substrate, Al.25Ga.75As on a GaAs substrate, Al.30Ga.7OAs on a GaAs substrate, and GaSb on a GaSb substrate. Excitation was achieved through the use of the 514.0 nm line of an argon ion laser, and sample cooling was attained by use of a cryostat cooler using helium gas to attain a low temperature limit of 10°K. The GaAs and Al.30 ...