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Optical constants of PbTe have been derived in the fundamental gap region between 25 and 300°K. It is shown in this paper by a direct compatibility check through Kramers-Krönig inversion, that properly prepared thin films have the optical properties of homogeneous material. A physical model is used to relate the optical edge and the refractive index signularity to the band gap and a value of the low-temperature dispersion of the refractive index is given, for the low-energy side of the singularity where photoelectronic phenomena take place. The precise shape of the refractive index singularity, and its relation to band tailing are discussed. The values of the optical band-gap temperature coefficient are compared with results from other authors. 相似文献
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F. Charfi M. Zouaghi A. Joullie M. Balkanski Ch. Hirlimann 《physica status solidi b》1980,98(2):709-714
The Raman spectra of Ga1–xAlxSb alloys (x > 0.2) exhibit at low frequencies two peaks: 118 and 150 cm−1 which are attributed to the presence of Sb in the transition region between surface oxide and bulk material. The evolution of this peaks with concentration x and temperature is investigated. The analogy between the experimental results obtained on Ga1–xAlxSb and those obtained on binary oxidized III–V compounds lead to the demonstration that the peaks 118 and 150 cm−1 are the vibrational modes of the Sb-enriched layer resulting from the preferential oxidization of the group III element. 相似文献
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A prospective view is taken of a new field of optical spectroscopy, unifying resonance Raman scattering and luminescence, with main emphasis on conceptual and theoretical aspects. The method consists in explicitly exploiting two independent sets of probes, ( e , ω, k ) and (e′, ω′, k′), i. e. polarization, frequency, and wave vector of incident and scattered photons, respectively. As compared with absorption spectroscopy, where one has only one set of probes ( e , ω, k ), the secondary emission spectroscopy gives higher information about the dynamics of the material: interaction in the intermediate states or relaxation, characterized experimentally and theoretically by the secondary emission intensity Is( e , ω, k; e′, ω′, k′), which is a measure of polarization-, energy-, and momentum-correlation of incident and scattered photons. 相似文献
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T. Sekine C. Julien M. Jouanne M. Weber I. Samaras M. Balkanski 《physica status solidi b》1991,168(1):103-111
In order to explain new peaks in the Raman spectra of MoS2 after intercalation with Li, the lattice dynamics in LixMoS2 is calculated by applying the central force model. It is found that they can be attributed to new vibrational modes in which the intercalant atoms strongly vibrate against the host lattice. The force constants between Li and S atoms are much smaller than the intralayer force constants and have almost the same order value as the interlayer ones. 相似文献
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Ion implanted silicon with two types of impurities is studied using Raman scattering. The splitting of the localized modes into two pair modes is observed. In the case of 10B 31P pairs the two modes are ω ∥ = 650 cm−1, ω ⊥ = 620 cm−1, and for 11B 31P pairs, ω ∥ = 628 cm−1, ω ⊥ = 605 cm−1. Results for B As pairs in silicon are also reported. It is believed that for the first time the second order Raman scattering by pair modes is observed. The second order spectrum gives information about the density of states of these modes. 相似文献
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J. Weszka M. Balkanski M. Jouanne D. I. Pishchikov S. F. Marenkin 《physica status solidi b》1992,171(1):275-281
Raman scattering in ZnAs2 monoclinic crystals is studied at room temperature in backward geometry. Features within the 190 to 270 cm−1 frequency interval are due to As-chain modes. Low frequency features within the 10 to 100 cm−1 area are attributed to modes with considerable contribution from Zn atoms involved. 相似文献
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Transmission measurements are reported on highly phosphorous-doped n-type Si, at three different temperatures 300, 85, and 35°K, and for carrier densities ranging from 6 × 1018 to 4.9 × 1020 cm−3. Below the fundamental energy gap, the data are analysed in terms of three different processes: free carrier absorption, indirect transitions including the phonon contribution as well as the impurity or electron—electron scattering, and interconduction-band transitions. The absorption band due to inter-conduction-band transitions is observed to shift to higher wavelengths, when the doping increases. An explanation is given, taking into account the rise of the Fermi level in the conduction band. 相似文献