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Optical absorption in MnGaInS4 single crystals has been studied. Direct and indirect optical transitions are found to occur in the range of photon energies
of 2.37–2.74 eV and in the temperature range of 83–270 K. The temperature dependence of the band gap has been determined;
its temperature coefficients E
gd
and E
gi
are −5.06 × 10−4 and −5.35 × 10−4 eV/K, respectively. MnGaInS4 single crystals exhibit anisotropy in polarized light at the absorption edge; the nature of
this anisotropy is explained. 相似文献
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Technical Physics - The spectral distribution of photoconductivity and the temperature dependence of photocurrent in MnGaInS4 single crystals have been investigated. Photoconductivity spectra... 相似文献
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Optical absorption in MnIn2S4 single crystals has been studied. Direct and indirect optical transitions are found to occur at photon energies of 1.90?C2.16 eV in the temperature range of 80?C342 K. The temperature dependence of the band gap is determined; its temperature coefficients E gd and E gi are found to be ?4.84 × 10?4 and ?6.33 × 10?4 eV/K, respectively. The electron-phonon interaction is the main mechanism of the temperature shift of the intrinsic-absorption edge. MnIn2S4 single crystals exhibit anisotropy in polarized light at the absorption edge in the temperature range of 90?C190 K; the nature of this anisotropy is explained. 相似文献
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G.K. Aslanov G.M. Niftiev O.B. Tagiev CH.M. Briskina V.F. Zolin V.M. Markushev 《Journal of luminescence》1985,33(2):135-140
Photoluminescence of chalcogenides of europium-gallium, EuGa2S4 and EuGa2Se4, doped with neodymium is investigated. The positions of Stark levels are determined from the spectra. The symmetry of luminescence centres is shown to be lower than cubic and the existence of nonequivalent centers is established. At 77 K the decay time of luminescence from the excited levels of Nd3+ depends on the spin of the states. That indicates a slow relaxation rate in the crystals under investigation. It is probable that these crystals can be used as effective luminophores. 相似文献
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Optical absorption of MnGa2S4 single crystals is studied at two light polarizations (E ||C and E⊥ C). The polarization splitting of the absorption edge points to a splitting of the valence band of MnGa2S4. A contribution to the crystal-field splitting is made by two factors, namely, by a difference in the pseudopotential of cationic sublattice atoms and by tetragonal compression of the lattice along the C axis. A scheme of optical transitions in MnGa2S4 in the Brillouin zone center is suggested, according to which the optical transitions Г3 + Г4 → Г1 occur in the polarization E ⊥ C, and the Г2 → Г1 transitions occur in the polarization E || C. 相似文献
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The results of studying optical-absorption and spectral curves of photoconductivity in MnGaInS4 single crystals are presented for two light polarizations (E || C and E ⊥ C). The intrinsic absorption edge and the band-gap width of MnGaInS4 single crystals in polarized light are determined. The anisotropy of optical absorption and photoconductivity spectrum of MnGaInS4 single crystals is observed. It is suggested that the polarization splitting of the absorption edge is related to the splitting of the MnGaInS4 valence band. 相似文献
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The frequency and temperature dependences of the ac capacitance and resistivity of FeIn2S4 semiconductors are studied. Resonances are observed at certain temperatures in the frequency range (2.5–5.0) × 105 Hz. The permittivity of the crystals and the activation energy of charge carriers are determined. It is found that electrical
conduction in the given temperature interval is governed by an activation mechanism. The activation energy is frequency-dependent,
because the relaxation time of barrier layers decreases with rising frequency. 相似文献
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