Self-Energy corrections to DFT-LDA Gaps of Realistic Carbon Nanotubes

2001 ◽  
Vol 703 ◽  
Author(s):  
Guido Satta ◽  
Giancarlo Cappellini ◽  
Francesco Casula
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Electronic Properties ◽  
Crucial Point ◽  
Excitation Energies ◽  
Self Energy ◽  
Microelectronic Devices ◽  
First Time

ABSTRACTSince their discovery carbon nanotubes have attracted much interest for their peculiar electronic properties which go from metalic to semiconducting behaviour, depending both on diameter and chirality. The exact vaue of their band gap is obviously a crucial point to be addressed because it enters in the nanotube application as microelectronic devices. By making use of an efficient GW scheme, previousy tested on bulk systems, as well as of a model screening function, we obtained for the first time excitation energies and band-gap vaues for carbon nanotubes. Results for (6,0) and (7,0) will be presented and discussed.

scholarly journals Charge transfer in steam purified arc discharge single walled carbon nanotubes filled with lutetium halides

2020 ◽  
Vol 22 (18) ◽  
pp. 10063-10075
Author(s):  
Ana Santidrián ◽  
Magdalena Kierkowicz ◽  
Elzbieta Pach ◽  
Denisa Darvasiová ◽  
Belén Ballesteros ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Electronic Properties ◽  
Arc Discharge ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Effect Of Doping

In the present work, the effect of doping on electronic properties in bulk purified and filled arc-discharge single-walled carbon nanotubes samples is studied for the first time by in situ Raman spectroelectrochemical method.

scholarly journals A tool box to ascertain the nature of doping and photoresponse in single-walled carbon nanotubes

2019 ◽  
Vol 21 (7) ◽  
pp. 4063-4071 ◽  
Author(s):  
Ana Santidrián ◽  
José M. González-Domínguez ◽  
Valentin Diez-Cabanes ◽  
Javier Hernández-Ferrer ◽  
Wolfgang K. Maser ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
First Time

The effect of doping on the electronic properties in bulk single-walled carbon nanotube (SWCNT) samples is studied for the first time using a new in situ Raman spectroelectrochemical method, and further verified by DFT calculations and photoresponse.

scholarly journals Effect of Nitrogen Impurity on Electronic Properties of Boron Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Sandeep Kumar Jain ◽  
Pankaj Srivastava
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Nitrogen Doping ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Functional Theory ◽  
Impurity Atoms ◽  
Nitrogen Impurity ◽  
First Time

For the first time we present electronic band structure and density of states for nitrogen doped hexagonal ultrathin boron nanotubes in the framework of density functional theory. The considered models of nanotubes below 5 Å diameter are armchair (3,3), zigzag (5,0), and chiral (4,2). The impurity chosen for the study is nitrogen and concentration of impurity atoms is limited to two. The study reveals that (3,3) BNT retains its metallic nature after nitrogen doping. However, metallicity gets increased which is attributed by the excess electrons of nitrogen. Further, it also brings out that (5,0) BNT which is originally metal transforms into semiconductor after nitrogen interaction and the band gap at G point increases with the impurity. Moreover, the band gap of (4,2) BNT reduces significantly and turns into semimetal for nitrogen doping. Thus, the nitrogen impurity has the predominant effect on the electronic properties of BNTs and therefore can be regarded as suitable candidates for nanoelectronic and field emission devices.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Continuous Wave ◽  
Silica Surface ◽  
Multi Wall Carbon Nanotubes ◽  
Composite Formation ◽  
Multi Walled Carbon Nanotubes ◽  
Glass Surfaces ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Scanning Electron

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.

New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

2019 ◽  
Author(s):  
Victor Y. Suzuki ◽  
Luís Henrique Cardozo Amorin ◽  
Natália H. de Paula ◽  
Anderson R. Albuquerque ◽  
Julio Ricardo Sambrano ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Material Design ◽  
Photocatalytic Properties ◽  
Critical Parameters ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Theoretical Approaches ◽  
Nanoparticles Synthesis ◽  
First Time

<p>We report, for the first time, new insights into the nature of the band gap of <a>CuGeO<sub>3</sub> </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.</p> <p><b> </b></p>

scholarly journals Self-Photoluminescence of Unzipped Multi-Walled Carbon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1632
Author(s):  
Mengyao Chen ◽  
Xiaohua Qi ◽  
Wenna Zhang ◽  
Na Yang ◽  
Di Yang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Hummers Method ◽  
Light Region ◽  
Munk Function ◽  
Pristine Cnts ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Modified Hummers Method ◽  
Etching Effect

Unzipping of carbon nanotubes (CNTs) has been widely explored to obtain new nanocarbon structures with promising properties. In this work, we report that unzipping of CNTs according to the well-established modified Hummers method produces unzipped CNTs (uCNTs) that exhibit self-photoluminescence that depends on the diameter of pristine CNTs. The uCNTs were characterized using FTIR spectroscopy, XRD, XPS, and Raman spectroscopy indicating that unzipping is accompanied by the introduction of defects and oxygen-containing functional groups. The morphology of CNTs and uCNTs was determined by TEM showing longitude unzipping of CNTs. Our study shows that increasing the diameter of pristine CNTs results in decreasing the edge etching effect and decreasing the functionality of uCNTs. Based on the UV-Vis spectra, the band gap of uCNTs was calculated using the Kubelka–Munk function. The band gap of uCNTs increased with decreasing diameter of pristine CNTs. The uCNTs exhibited photoluminescence with a good emission in the visible light region. The uCNTs with the largest band gap and the highest oxygen content had the strongest fluorescence intensity. Moreover, different metal ions produced different degrees of fluorescence quenching for uCNT-15, which verified the self-photoluminescence of uCNTs.

Gap solitons supported by an optical lattice in biased photorefractive crystals having both the linear and quadratic electro-optic effect

2020 ◽  
Vol 75 (8) ◽  
pp. 749-756
Author(s):  
Aavishkar Katti ◽  
Chittaranjan P. Katti
Keyword(s):  
Band Gap ◽  
Optical Lattice ◽  
Propagation Constant ◽  
Gap Soliton ◽  
Electro Optic ◽  
Quadratic Nonlinearities ◽  
Existence And Stability ◽  
Gap Solitons ◽  
Finite Band ◽  
First Time

AbstractWe investigate the existence and stability of gap solitons supported by an optical lattice in biased photorefractive (PR) crystals having both the linear and quadratic electro-optic effect. Such PR crystals have an interesting interplay between the linear and quadratic nonlinearities. Gap solitons are predicted for the first time in such novel PR media. Taking a relevant example (PMN-0.33PT), we find that the gap solitons in the first finite bandgap are single humped, positive and symmetric solitons while those in the second finite band gap are antisymmetric and double humped. The power of the gap soliton depends upon the value of the axial propagation constant. We delineate three power regimes and study the gap soliton profiles in each region. The gap solitons in the first finite band gap are not linearly stable while those in the second finite band gap are found to be stable against small perturbations. We study their stability properties in detail throughout the finite band gaps. The interplay between the linear and quadratic electro-optic effect is studied by investigating the spatial profiles and stability of the gap solitons for different ratios of the linear and quadratic nonlinear coefficients.

scholarly journals Supramolecular structures of terbium(iii) porphyrin double-decker complexes on a single-walled carbon nanotube surface

RSC Advances ◽  
2019 ◽  
Vol 9 (48) ◽  
pp. 28135-28145
Author(s):  
Ahmed I. A. Abd El-Mageed ◽  
Takuji Ogawa
Keyword(s):  
Carbon Nanotubes ◽  
Scanning Probe Microscopy ◽  
Single Walled Carbon Nanotubes ◽  
Supramolecular Structures ◽  
Scanning Probe ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Double Decker ◽  
Walled Carbon Nanotubes ◽  
First Time

For the first time, using scanning probe microscopy, the supramolecular structures of terbium porphyrin double-decker complexes were observed on single-walled carbon nanotubes surfaces, where the molecules formed a well-ordered self-assembled array.

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