Ellipsometric determination of the optical constants of C60 (Buckminsterfullerene) films

Ren, S. L.; Wang, Y.; Rao, Apparao M.; McRae, E.; Holden, J. M.; Häger, Tobias; Wang, Kai‐An; Lee, Wen-Tse; Ni, Hangjian; Selegue, John P.; Eklund, P. C.

doi:10.1063/1.105907

Cited by 248 publications

(95 citation statements)

References 17 publications

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“…For the two finite nanotubes considered, the polarizabilities per carbon atom, ␣ 0 ͑w 1 ͒ = 3.2 and ␣ 0 ͑w 2 ͒ = 2.45 Å 3 , are of the same order as for the C 60 fullerene, 1.38-1.42 Å 3 per atom. 31 …”

Section: A Binding Energy and Interaction Energy With The External Ementioning

confidence: 99%

Half-metallic finite zigzag single-walled carbon nanotubes from first principles

et al. 2008

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Density-functional calculations predict half-metallicity in zigzag single-walled carbon nanotubes of finite length with the two ends saturated with hydrogen. We have analyzed the change of the ␣-and ␤-spin electronic gaps under the influence of an electric field applied along the nanotube axis. The half-metallic behavior, in which the electronic gap is zero for one spin flavor and nonzero for the other, is obtained for a critical electric field of 3.0/ w V / Å, where w is the length of the nanotube. This critical field is the same as that predicted for graphene nanoribbons. By a detailed analysis of the spin structure of the ground state, we show the relevance of the edge states, electronic states spatially localized at the carbon atoms of the nanotube boundaries, on the on-set of half-metallicity, and on the magnetic properties of the finite semiconducting zigzag nanotubes.

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Section: A Binding Energy and Interaction Energy With The External Ementioning

confidence: 99%

Half-metallic finite zigzag single-walled carbon nanotubes from first principles

et al. 2008

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“…Ellipsometry can be used to measure the thickness of the C 6 o films as they are deposited. 28 By variation of the substrate material and crystalline orientation, and by variation of the film growth temperature, the crystallite size and microstructure of the film can be varied. Single crystals can be grown either from solution using solvents such as CS 2 , hexane and toluene, or by vacuum sublimation.…”

Section: Fig 4 (A) Gel Permeation Chromatogram Of Fullerenes Obtainmentioning

confidence: 99%

“…25 in which the transmittance for solid C 6 o is compared with that for C 6 o dissolved in decalin. 28 The optical properties of solid C 6 o and C 70 have been studied over a wide frequency range using the variable angle spectroscopic ellipsometry (VASE) technique. 28 ' 179 From the VASE measurements, the complex refractive index, h(co) = n(a>) + ik(eo), is determined, which is related to the complex optical dielectric function e(co) = €i(w) + ie 2 …”

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confidence: 99%

Fullerenes

1993

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A review of the structure and properties of fullerenes is presented. Emphasis is given to their behavior as molecular solids. The structure and property modifications produced by alkali-metal doping are summarized, including modification to the electronic structure, lattice modes, transport, and optical properties. Particular emphasis is given to the alkali-metal-doped fullerenes because of their importance as superconductors. A review of the structure and properties of fullerene-based graphene tubules is also given, including a model for their one-dimensional electronic band structure. Potential applications for fullerene-based materials are suggested.

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“…Coulomb interaction effects on the absorption spectra and the optical nonlinearity have been also studied [8]. We have found that the linear absorption spectra of C 60 and C 70 are well explained by the Frenkel exciton picture [9] except for the charge transfer exciton feature around the excitation energy 2.8 eV of the C 60 solids [2]. Coulomb interaction effects reduce the magnitude of the optical nonlinearity from that of the free electron calculation [8], and thus the intermolecular interaction effects have turned out to be important.…”

mentioning

confidence: 86%

“…A lot of optical experiments have been performed, and excitation properties due to π-electrons delocalized on molecular surfaces have been measured. For example, the optical absorption spectra of C 60 and C 70 [1,2] have been reported, and the large optical nonlinearity of C 60 [3,4] has been found. The absorption spectra of higher fullerenes (C 76 , C 78 , C 84 , etc.)…”

Section: Phason Lines and Linear Absorptionmentioning

confidence: 99%

Nonlinear optical response from excitons in C60,C70, and higher fullerenes

Harigaya¹

1998

Journal of Luminescence

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The optical excitations in C 60 and higher fullerenes, including isomers of C 76 , C 78 , and C 84 , are theoretically investigated. We use a tight binding model with long-range Coulomb interactions, treated by the Hartree-Fock and configuration-interaction methods. We find that the optical excitations in the energy region smaller than about 4 eV have most of their amplitudes at the pentagons. The oscillator strengths of projected absorption almost accord with those of the total absorption. Next, off-resonant third order susceptibilities are investigated. We find that third order susceptibilities of higher fullerenes are a few times larger than those of C 60 . The magnitude of nonlinearity increases as the optical gap decreases in higher fullerenes. The nonlinearity is nearly proportional to the fourth power of the carbon number when the onsite Coulomb repulsion is 2t or 4t, t being the nearest neighbor hopping integral. This result, indicating important roles of Coulomb interactions, agrees with quantum chemical calculations of higher fullerenes. Phason Lines and Linear AbsorptionRecently, the fullerene family C N with hollow cage structures has been intensively investigated. A lot of optical experiments have been performed, and excitation properties due to π-electrons delocalized on molecular surfaces have been measured. For example, the optical absorption spectra of C 60 and C 70 [1,2] have been reported, and the large optical nonlinearity of C 60 [3,4] has been found. The absorption spectra of higher fullerenes (C 76 , C 78 , C 84 , etc.) have also been obtained [5,6]. For theoretical studies, we have applied a tight binding model [7] to C 60 , and have analyzed the nonlinear optical properties. Coulomb interaction effects on the absorption spectra and the optical nonlinearity have been also studied [8]. We have found that the linear absorption spectra of C 60 and C 70 are well explained by the Frenkel exciton picture [9] except for the charge transfer exciton feature around the excitation energy 2.8 eV of the C 60 solids [2]. Coulomb interaction effects reduce the magnitude of the optical nonlinearity from that of the free electron calculation [8], and thus the intermolecular interaction effects have turned out to be important.In the previous paper [10], we have extended the calculation of C 60 [9] to one of the higher fullerenes C 76 . We have discussed variations of the optical spectral shape in relation to the symmetry reduction from C 60 and C 70 to C 76 : the optical gap decreases and the spectra exhibit a larger number of small structures in the dependences on the excitation energy. These properties seem to be natural when we take into account of the complex surface patterns composed of pentagons and hexagons. In order to understand the patterns clearly, the idea of the phason lines (Fig. 1) has been introduced [11] using the projection method on the honeycomb lattice plane [12]. There are twelve pentagons in C 76 . Six of them cluster on the honeycomb lattice, with one hexagon between the nei...

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Ellipsometric determination of the optical constants of C60 (Buckminsterfullerene) films

Cited by 248 publications

References 17 publications

Half-metallic finite zigzag single-walled carbon nanotubes from first principles

Half-metallic finite zigzag single-walled carbon nanotubes from first principles

Fullerenes

Nonlinear optical response from excitons in C60,C70, and higher fullerenes

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