Now showing items 1-18 of 18

    • Ab-initio electron transport calculations of carbon based string structures 

      Tongay, S.; Senger, R. T.; Dag, S.; Ciraci, S. (American Physical Society, 2004)
      The new stable structures of carbon-based strings and their unusual electronic transport properties were discussed. Total energy and electronic structure calculations using first principles pseudopotential plane wave method ...
    • All-fiber Yb-doped laser mode-locked by nanotubes 

      Zhang, U.Z.; Popa, D.; Sun, Z.; Hasan, T.; Ferrari, A.C.; Ilday F.O. (IEEE Computer Society, 2013)
      Single-wall carbon nanotubes (SWNTs) and graphene have emerged as promising saturable absorbers (SAs), due to their broad operation bandwidth and fast recovery times [1-3]. However, Yb-doped fiber lasers mode-locked using ...
    • Atomic strings of group IV, III-V, and II-VI elements 

      Tongay, S.; Durgun, E.; Ciraci, S. (American Institute of Physics, 2004)
      A systematic first-principles study of atomic strings made by group IV, III-V, and II-VI elements has revealed interesting mechanical, electronic, and transport properties. The double bond structure underlies their unusual ...
    • Chemically specific dynamic characterization of photovoltaic and photoconductivity effects of surface nanostructures 

      Ekiz, O. Ö.; Mizrak, K.; Dâna, A. (American Chemical Society, 2010)
      We report characterization of photovoltaic and photoconductivity effects on nanostructured surfaces through light induced changes in the X-ray photoelectron spectra (XPS). The technique combines the chemical specificity ...
    • Chiral single-wall gold nanotubes 

      Senger, R. T.; Dag, S.; Ciraci, S. (American Physical Society, 2004)
      The formation of freestanding and tip-suspended chiral-wall (n,m) nanotubes, which were composed of helical atomic strands, from gold atoms was investigated using first-principles calculations, where (n,m) notation defines ...
    • DFT studies of CNT-functionalized uracil-acetate hybrids 

      Mirzaei, M.; Gulseren, O. (Elsevier, 2015)
      Calculations based on density functional theory (DFT) have been performed to investigate the stabilities and properties of hybrid structures consisting of a molecular carbon nanotube (CNT) and uracil acetate (UA) counterparts. ...
    • Electronic structure of the contact between carbon nanotube and metal electrodes 

      Dag, S.; Gülseren, O.; Ciraci, S.; Yildirim, T. (American Institute of Physics, 2003)
      Our first-principles study of the contact between a semiconducting single-walled carbon nanotube ~s-SWNT! and metal electrodes shows that the electronic structure and potential depend strongly on the type of metal. The ...
    • Energetics and Electronic Structures of Individual Atoms Adsorbed on Carbon Nanotubes 

      Durgun, E.; Dag, S.; Ciraci, S.; Gülseren, O. (American Chemical Society, 2004)
      The adsorption of individual atoms on the semiconducting and metallic single-walled carbon nanotubes (SWNT) has been investigated by using the first principles pseudopotential plane wave method within density functional ...
    • Functionalized carbon nanotubes and device applications 

      Ciraci, S.; Dag, S.; Yildirim, T.; Gülseren, O.; Senger, R. T. (Institute of Physics Publishing Ltd., 2004)
      Carbon nanotubes, in which the two-dimensional hexagonal lattice of graphene is transformed into a quasi-one-dimensional lattice by conserving the local bond arrangement, provide several structural parameters for engineering ...
    • High conducting nanowires obtained from uniform titanium covered carbon nanotubes 

      Daǧ, S.; Durgun, E.; Çiraci, S. (2005)
      We have shown that Ti atoms can form continuous coating of carbon nanotubes at different amount of coverage. The circular cross section changes to a square-like form, and the semiconducting tube becomes ferromagnetic metal ...
    • Intimate relationship between structural deformation and properties of single-walled carbon nanotubes 

      Yildirim, T.; Gulseren O.; Ciraci, S. (2002)
      Carbon nanotubes continue to surprise scientists with their novel properties. Recently we have discovered many intimate relationships between structural deformation and the properties of single-walled nanotubes (SWNT), ...
    • Magic gold nanotubes 

      Senger, R.T.; Daǧ, S.; Çiraci, S. (2005)
      In recent ultra-high-vacuum transmission-electron-microscopy experiments evidence is found for the formation of suspended gold single-wall nanotubes (SWNTs) composed of five helical strands. Similar to carbon nanotubes, ...
    • Patterned carbon nanotubes as a new three-dimensional scaffold for mesenchymal stem cells 

      Bitirim V.C.; Kucukayan-Dogu G.; Bengu, E.; Akcali, K.C. (2013)
      We investigated the cellular adhesive features of mesenchymal stem cells (MSC) on non-coated and collagen coated patterned and vertically aligned carbon nanotube (CNT) structures mimicking the natural extra cellular matrix ...
    • Quantum effects in electrical and thermal transport through nanowires 

      Ciraci, S.; Buldum, A.; Batra, I. P. (Institute of Physics Publishing, 2001)
      Nanowires, point contacts and metallic single-wall carbon nanotubes are one-dimensional nanostructures which display important size-dependent quantum effects. Quantization due to the transverse confinement and resultant ...
    • Structural and electronic properties of carbon-based materials 

      Kılıç, Çetin (Bilkent University, 2000)
      In this thesis, some carbon-based materials in nano scale have been investigated by using first-principles methods as well as transferable tight-binding and empirical potential models. The focus of interest has been in ...
    • Theoretical study of hydrogen adsorption in Ti-decorated capped carbon nanotube 

      Niaz S.; Abbasian H.; Badar M.A.; Anwar-ul-Haq M.; Karayel A. (Taylor and Francis Ltd., 2017)
      We present ab initio study using dispersion-corrected density functional theory calculations to investigate the hydrogen interaction with Ti-coated, one end closed, single-walled carbon nanotube (SWCNT). Our results ...
    • Titanium-decorated carbon nanotubes as a potential high-capacity hydrogen storage medium 

      Yildirim, T.; Ciraci, S. (American Physical Society, 2005)
      We report a first-principles study, which demonstrates that a single Ti atom coated on a single-walled nanotube (SWNT) binds up to four hydrogen molecules. The first H2 adsorption is dissociative with no energy barrier ...
    • Use of saccharides as solid-state precursors for the synthesis of carbon nanotubes 

      Kucukayan, G.; Kayacan, S.; Baykal, B.; Bengu, E. (Materials Research Society, 2008)
      Saccharides, ranging from simple table sugar (sucrose) to lactulose were successfully used as solid-state precursors for the synthesis of multi-walled carbon nanotubes (MWCNT). Dehydrated saccharide residues mixed with ...