Browsing by Keywords "Graphene"
Now showing items 21-40 of 100
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Electronic structure of graphene under the influence of external fields
(Bilkent University, 2012)In this thesis, the electronic structure of graphene under the influence of external fields such as strain or magnetic fields is investigated by using tight-binding method. Firstly, we study graphene for a band gap opening ... -
Enhanced memory effect with embedded graphene nanoplatelets in ZnO charge trapping layer
(AIP Publishing, 2014)A charge trapping memory with graphene nanoplatelets embedded in atomic layer deposited ZnO (GNIZ) is demonstrated. The memory shows a large threshold voltage Vt shift (4 V) at low operating voltage (6/-6 V), good retention ... -
Enhanced non-volatile memory characteristics with quattro-layer graphene nanoplatelets vs. 2.85-nm Si nanoparticles with asymmetric Al2O3/HfO2 tunnel oxide
(Springer New York LLC, 2015)In this work, we demonstrate a non-volatile metal-oxide semiconductor (MOS) memory with Quattro-layer graphene nanoplatelets as charge storage layer with asymmetric Al2O3/HfO2 tunnel oxide and we compare it to the ... -
Enhanced tunability of V-shaped plasmonic structures using ionic liquid gating and graphene
(Elsevier Ltd, 2016)Graphene is a strong candidate for active optoelectronic devices because of its electrostatically tunable optical response. Current substrate back-gating methods are unable to sustain high fields through graphene unless a ... -
Extraction and scattering analyses of 2D and bulk carriers in epitaxial graphene-on-SiC structure
(Elsevier BV, 2014-09)Hall effect measurements of a graphene-on-SiC system were carried out as a function of temperature (1.8-200 K) at a static magnetic field (0.51) With the analysis of temperature dependent single-field Hall data with the ... -
Femtosecond pulse generation from a Ti3+: Sapphire laser near 800 nm with voltage reconfigurable graphene saturable absorbers
(OSA - The Optical Society, 2017)We experimentally show that a voltage-controlled graphene-gold supercapacitor saturable absorber (VCG-gold-SA) can be operated as a fast saturable absorber with adjustable linear absorption at wavelengths as low as 795 nm. ... -
Femtosecond pulse generation from an extended cavity Cr4+: Forsterite laser using graphene on YAG
(Optical Society of America, 2013)A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near ... -
First-principles calculations of Pd-terminated symmetrical armchair graphene nanoribbons
(Elsevier, 2013)The effects of Palladium (Pd) termination on the electronic properties of armchair graphene nanoribbons (AGNRs) were calculated by using ab initio calculations. After a geometric optimization process, the electronic band ... -
First-principles investigation of graphitic nanostructures
(Bilkent University, 2013)In this thesis, first-principles investigations of several graphene related nanosystems based on density functional theory are presented. First, the electronic structure of several graphene nano-ribbons both in 1D and ... -
Flexible strain sensors based on electrostatically actuated graphene flakes
(Institute of Physics Publishing, 2015)In this paper we present flexible strain sensors made of graphene flakes fabricated, characterized, and analyzed for the electrical actuation and readout of their mechanical vibratory response in strain-sensing applications. ... -
Focusing of THz waves with a microsize parabolic reflector made of graphene in the free space
(Springer International Publishing, 2017)Background: The scattering of H- and E-polarized plane waves by a two-dimensional (2-D) parabolic reflector made of graphene and placed in the free space is studied numerically. Methods: To obtain accurate results we use ... -
Frictional properties of quasi-two-dimensional materials from the Prandtl-Tomlinson model
(Bilkent University, 2016-09)Tribology, the study of friction, is both an old theoretical problem in physics and an area of great practical importance. The invention of experimental instruments such as Atomic Force Microscope (AFM) has lead to the ... -
Functionalization of graphene and stoichiometric graphene derivatives
(Bilkent University, 2011)Re ent developments in experimental te hniques have made the design and produ tion of materials at nanos ale possible. In parti ular, graphene has been the fo us of resear h in diverse elds owing to high mobility ... -
Generation of Sub-20-fs Pulses From a Graphene Mode-Locked Laser
(OSA - The Optical Society, 2017)We demonstrate, what is to our knowledge, the shortest pulses directly generated to date from a solid-state laser, mode locked with a graphene saturable absorber (GSA). In the experiments, a low-threshold diode-pumped ... -
Glycine self-assembled on graphene enhances the solar absorbance performance
(Elsevier, 2019)Despite its high solar absorbance and surface coating abilities, pristine graphene as a semimetal is not promising for photovoltaic applications. In this study, we predict that Glycine (Gly), an amino acid, which is ... -
Graphene and carbon nanotubes interfaced electrochemical nanobiosensors for the detection of SARS-CoV-2 (COVID-19) and other respiratory viral infections: A review
(Elsevier BV, 2021-10)Recent COVID-19 pandemic has claimed millions of lives due to lack of a rapid diagnostic tool. Global scientific community is now making joint efforts on developing rapid and accurate diagnostic tools for early detection ... -
Graphene based high frequency electronics
(Bilkent University, 2010)Recent advances in chemical vapor deposition of graphene on large area substrates stimulate a significant research effort in order to search for new applications of graphene in the field of unusual electronics such as ... -
Graphene based optoelectronics in the visible spectrum
(Bilkent University, 2015)Graphene, a two dimensional crystal of carbon atoms, emerges as a viable material for optoelectronics because of its electrically-tunable broadband optical properties. Optical response of graphene at visible and near ... -
Graphene based terahertz phase modulators
(IOP Publishing, 2018)Electrical control of amplitude and phase of terahertz radiation (THz) is the key technological challenge for high resolution and noninvasive THz imaging. The lack of active materials and devices hinders the realization ... -
Graphene field effect devices operating in differential circuit configuration
(Elsevier, 2015)We study the concept of a basic building block for circuits using differential signaling and being based on graphene field effect devices. We fabricated a number of top-gated graphene FETs using commercially available ...
