Optical spectra of Si<i>x</i>Ge1−<i>x</i> alloys

Humlíček, Josef; Garriga, M.; Alonso, M. I.; Cardona, M.

doi:10.1063/1.342720

Cited by 257 publications

(117 citation statements)

References 12 publications

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“…3 we compare our calculated LDA+U SIC absorption coefficient with measured absorption by Humlicek et al [19]. Overall, we find a very good qualitative agreement between the calculated and the measured results.…”

Section: Fig 1: the Band-gap Energies Of Si 1−x Ge X At γ-L And ∆-Psupporting

confidence: 64%

Electronic band-edge structure, effective masses, and optical absorption of Si1-xGe x using an extended FPLAPW/VCA/LDA+U computational method

Persson¹,

Nur²,

Willander³

et al. 2006

Braz. J. Phys.

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Electronic band-edge structure and optical properties of Si 1−x Ge x are investigated theoretically emloying a full-potential linearized augmented plane wave (FPLAPW) method. The exchange-correlation potential in the local density approximation (LDA) is corrected by an on-site Coulomb potential (i.e., within the LDA+U SIC approach) acting asymmetrically on the atomic-like orbitals in the muffin-tin spheres. The electronic structure of the Si 1−x Ge x is calculated self-consistently, assuming a T d symmetrized Hamiltonian and a linear behavior of the valence-band eigenfunctions for Si, SiGe, and Ge with respect to Ge composition x, assuming randomly alloyed crystal structure. i.e., a "virtual-crystal like" approximation (VCA). We show that this approach yields accurate band-gap energies, effective masses, dielectric function, and optical properties of Si 1−x Ge x . We perform absorption measurements showing the band-gap energy for x < 0.25.

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Section: Fig 1: the Band-gap Energies Of Si 1−x Ge X At γ-L And ∆-Psupporting

confidence: 64%

Electronic band-edge structure, effective masses, and optical absorption of Si1-xGe x using an extended FPLAPW/VCA/LDA+U computational method

Persson¹,

Nur²,

Willander³

et al. 2006

Braz. J. Phys.

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show abstract

“…While the broadening and reduction in amplitude is consistent with previous studies of doped GaAs, these works revealed a red shifting of both the E 1 and E 1 + ∆ 1 transitions, whereas we observe a blue shifting. 32 Additionally, in Ga 1−x Mn x As the two peaks appear to merge. As we discuss in sec.…”

Section: B Modeling the Optical Constantsmentioning

confidence: 97%

Ellipsometric study of the electronic structure ofGa1−xMnxAsand low-temperature
Burch
¹
,
Stephens
²
,
Kawakami
³

et al. 2004
Phys. Rev. B

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We have measured the optical constants of Ga 1−x Mn x As from 0.62 eV to 6 eV, using spectroscopic ellipsometry. The second derivatives of the dielectric function are examined through a critical point analysis. The E 1 critical point shifts to higher energies with increased doping of Mn, while all other critical points appear unaffected. The evolution of the critical points results from the interplay between band gap renormalization from ionized impurities and sp-d hybridization of the Mn induced impurity band and GaAs valence and conductions bands.

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“…In quenching, the excitation energy of the fluorophore is transferred to electronic excitations in the metal, which are then dissipated via Ohmic loss processes. Thus, the quenching efficiency is ultimately proportional to the imaginary part of the dielectric function, which, for metals, can be relatively large, yet for dielectrics can be very nearly zero: at 600 nm, the imaginary part of the dielectric function is 1.366 for Au [46], [47], 0.104 for Si [48], [49], and zero for crystalline SiO 2 (quartz) [47]. The quenching efficiency is also dependent on the geometry of the tip [39].…”

Section: B Fluorescence Reductionmentioning

confidence: 99%

Nanoscale Fluorescence Microscopy Using Carbon Nanotubes

Mangum

Xie

et al. 2008

IEEE J. Select. Topics Quantum Electron.

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Abstract-We demonstrate the first reported use of single-walled carbon nanotubes as nano-optical probes in apertureless nearfield fluorescence microscopy. We show that, in contrast to silicon probes, carbon nanotubes always cause strong fluorescence quenching when used to image dye-doped polystyrene spheres and Cd-Se quantum dots. For quantum dots, the carbon nanotubes induce very strong near-field contrast with a spatial resolution of ∼20 nm. Images of dye-doped spheres exhibit crescent-shaped artifacts caused by distortions in the surface water layer found in ambient conditions. Index Terms-Atomic force microscopy (AFM), carbon nanotubes, fluorescence microscopy, fluorescence quenching, nanooptics, near-field optics.

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Optical spectra of SixGe1−x alloys

Cited by 257 publications

References 12 publications

Electronic band-edge structure, effective masses, and optical absorption of Si1-xGe x using an extended FPLAPW/VCA/LDA+U computational method

Electronic band-edge structure, effective masses, and optical absorption of Si1-xGe x using an extended FPLAPW/VCA/LDA+U computational method

Ellipsometric study of the electronic structure ofGa1−xMnxAsand low-temperature
Burch
¹
,
Stephens
²
,
Kawakami
³

et al. 2004
Phys. Rev. B

Nanoscale Fluorescence Microscopy Using Carbon Nanotubes

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Optical spectra of SixGe1−x alloys

Cited by 257 publications

References 12 publications

Electronic band-edge structure, effective masses, and optical absorption of Si1-xGe x using an extended FPLAPW/VCA/LDA+U computational method

Electronic band-edge structure, effective masses, and optical absorption of Si1-xGe x using an extended FPLAPW/VCA/LDA+U computational method

Ellipsometric study of the electronic structure ofGa1−xMnxAsand low-temperatureBurch1, Stephens2, Kawakami3 et al. 2004Phys. Rev. B

Nanoscale Fluorescence Microscopy Using Carbon Nanotubes

Contact Info

Product

Resources

About

Ellipsometric study of the electronic structure ofGa1−xMnxAsand low-temperature
Burch
¹
,
Stephens
²
,
Kawakami
³

et al. 2004
Phys. Rev. B