The photoluminescence properties of
EuGa2S4:Er
polycrystals under 337.1 and 976 nm laser excitations versus temperature (78–500 K) are
presented. Under 337.1 nm excitation wavelength, a wide emission band corresponding to
Eu2+
ions in the visible range and emission lines of
Er3+
in the visible and near infrared were observed. These emissions were also observed under 976 nm
excitation wavelength with a two-photon absorption accompanied by a phonon assisted energy transfer
to Eu2+
ions. According to experimental conditions, energy transfers from
Eu2+ to
Er3+ and
from Er3+
to Eu2+
are highlighted.
Research study of volt-amperage properties (VAP) of [Formula: see text] crystals determined the mechanism of current flow though the studied samples and this mechanism is based on barrier Schottky emission and emission of Franklin–Paul. The dielectric constant of the material, height of the potential barrier on metal–semiconductor border, concentration of the traps and the effective mass of electrons are calculated.
Photoluminescence (PL) excitation and emission spectra of Ca(Al x Ga 1 -x ) 2 S 4 :Eu 2+ (х = 0.1, 0.2) crystals have been investigated at different temperatures (20-300 K) and europium concentrations (3, 5, 7%).The emission spectrum is a band peaking at 556 nm, which is due to 4f 6 5d → 4f 7 ( 8 S 7/2 ) transitions in the Eu 2+ion. An increase in the Eu 2+ concentration leads to an increase in the PL intensity by a factor of almost 3. Stokes shift ΔS = 0.32 eV, Huang-Rhys factor s = 10 ± 2, activation energy Е а = 0.02 and 0.03 eV, and lifetime τ = 250 ns are determined by analyzing the spectra.
Проведены исследования термолюминесценции (ТЛ) твердых растворов Ca(Alx Ga 1−x ) 2 S 4 : Eu 2+ (x = 0.1−0.3) после ультрафиолетового облучения ме-тодом линейного нагрева. Показано, что наблюдаемые максимумы ТЛ сложные и состоят из нескольких сильно перекрывающихся парциальных максимумов, определены энергия активации, сечение захвата, частотный фактор и концен-трация ловушечных уровней, ответственных за эти максимумы. С увеличением x интенсивность излучения и число пиков растет.
Photoluminescence properties of [Formula: see text] chalcogenide semiconductors have been studied under the impulse laser excitation in the range of 10–105 W/cm2 at room temperature. This study has shown that as a result of excitation, photoluminescence of [Formula: see text] is characterized by the emission in the interval of 450–575 nm with significant domination in the spectra line at 660 nm. Photoluminescence of [Formula: see text] quenches at wavelengths of 560 nm and 660 nm with constant time frames 258 ns and 326 ns, respectively. Moreover, the temperature measurements of photoluminescence were performed on the samples in the temperature range of 10–300 K.
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