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 SM ISO690:2012ZALAMAI, Victor, SYRBU, Nicolae, STAMOV, Ivan. Excitonic polaritons in ZnAs2. In: Materials Science and Condensed Matter Physics, Ed. 8-th Edition, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, Editia 8, p. 93. ISBN 978-9975-9787-1-2. |
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| Materials Science and Condensed Matter Physics Editia 8, 2016 |
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Conferința "International Conference on Materials Science and Condensed Matter Physics" 8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016 | ||||||
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Exciton polaritons of ZnAs2 nanocrystals were investigated. Parameters of singlet excitons (A) with Г2¯(z) symmetry and orthoexcitons (B) 2Г1¯(y)+Г2¯(x) were determined. Spectral dependences of normal and anomaly dispersions of refractive index were calculated from interferential reflection and transmission spectra. It was shown, that A and B excitonic series were due to by hole V1 and electron C1 bands. The values of effective masses of electrons (mc* = 0.10m0) and holes (mv1* = 0.89m0). It was revealed that the hole mass mv1* changes from 1.03m0 to 0.55m0 at temperature increasing from 10 K to 230 K and the electron mass mc* does not depend on temperature. The integral absorption A (eV-cm-1) for states n = 1, 2 and 3 Г2¯(z) excitons obeys to the dependence An - n-3 it is characteristic for S-type exctionic functions. Temperature dependences of ground states integral absorption for Г2¯(z) and Г2¯(х) excitons differ. The ground states C and D excitons formed by V3 - C1 and V4 - C1 bands were found out and its parameters were determined. Fig. 1, A - Wavelength modulated transmission spectra (ΔT/Δλ) of ZnAs2 crystals of 17 μm thickness measured in E c polarization. B - Temperature dependence ωs, ω0 and half-width absorption band ΔH. C - Temperature dependence of integral absorption of excitons Г2¯(z) and Г2¯(х) ground states (n = 1). Contours of wavelength modulated transmission spectra (ΔT/Δλ) in Ec polarization shift to longwavelengths with temperature increasing, fig. 1, A. Simultaneously the bands minima ωs and ω0 move apart energetically and its half-width (ΔH) changes, fig. 1, B. A ωs, ω0 and ΔH change gradient change in temperature range 100 - 130 K, what is evidence of different temperature shift coefficients of bands responsible for Г2¯(z) and Г2¯(х) exctionic lines. Quantitative estimates of integral absorption A (eV-cm-1) have been made for absorption coefficients received form KramersKronig analysis of reflection spectra for n = 1, 2 and 3 Г2¯(z) excitons. The integral absorptions A are equal to 0.104 eV-cm-1, 0.002 eV-cm-1 and 0.001 eV-cm-1 for excited state for n = 1, n =2 and n = 3 lines, respectively. This quantity measurements of integral absorption coefficient A for exctionic series Г2¯(z) shows that the integral absorption for lines n series subordinates to dependence An - n-3 that is typical for exciton envelope function of S-type. The integral absorption (A) for n = 1 line of Г2¯(х) excitons changes in the range 1.44 - 10 eV-cm-1 at temperature variation form 10 K to 230 K (see Fig. 1, C). |
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<?xml version='1.0' encoding='utf-8'?> <oai_dc:dc xmlns:dc='http://purl.org/dc/elements/1.1/' xmlns:oai_dc='http://www.openarchives.org/OAI/2.0/oai_dc/' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd'> <dc:creator>Zalamai, V.V.</dc:creator> <dc:creator>Sîrbu, N.N.</dc:creator> <dc:creator>Stamov, I.G.</dc:creator> <dc:date>2016</dc:date> <dc:description xml:lang='en'><p>Exciton polaritons of ZnAs2 nanocrystals were investigated. Parameters of singlet excitons (A) with Г2¯(z) symmetry and orthoexcitons (B) 2Г1¯(y)+Г2¯(x) were determined. Spectral dependences of normal and anomaly dispersions of refractive index were calculated from interferential reflection and transmission spectra. It was shown, that A and B excitonic series were due to by hole V1 and electron C1 bands. The values of effective masses of electrons (mc* = 0.10m0) and holes (mv1* = 0.89m0). It was revealed that the hole mass mv1* changes from 1.03m0 to 0.55m0 at temperature increasing from 10 K to 230 K and the electron mass mc* does not depend on temperature. The integral absorption A (eV-cm-1) for states n = 1, 2 and 3 Г2¯(z) excitons obeys to the dependence An - n-3 it is characteristic for S-type exctionic functions. Temperature dependences of ground states integral absorption for Г2¯(z) and Г2¯(х) excitons differ. The ground states C and D excitons formed by V3 - C1 and V4 - C1 bands were found out and its parameters were determined. Fig. 1, A - Wavelength modulated transmission spectra (ΔT/Δλ) of ZnAs2 crystals of 17 μm thickness measured in E c polarization. B - Temperature dependence ωs, ω0 and half-width absorption band ΔH. C - Temperature dependence of integral absorption of excitons Г2¯(z) and Г2¯(х) ground states (n = 1). Contours of wavelength modulated transmission spectra (ΔT/Δλ) in Ec polarization shift to longwavelengths with temperature increasing, fig. 1, A. Simultaneously the bands minima ωs and ω0 move apart energetically and its half-width (ΔH) changes, fig. 1, B. A ωs, ω0 and ΔH change gradient change in temperature range 100 - 130 K, what is evidence of different temperature shift coefficients of bands responsible for Г2¯(z) and Г2¯(х) exctionic lines. Quantitative estimates of integral absorption A (eV-cm-1) have been made for absorption coefficients received form KramersKronig analysis of reflection spectra for n = 1, 2 and 3 Г2¯(z) excitons. The integral absorptions A are equal to 0.104 eV-cm-1, 0.002 eV-cm-1 and 0.001 eV-cm-1 for excited state for n = 1, n =2 and n = 3 lines, respectively. This quantity measurements of integral absorption coefficient A for exctionic series Г2¯(z) shows that the integral absorption for lines n series subordinates to dependence An - n-3 that is typical for exciton envelope function of S-type. The integral absorption (A) for n = 1 line of Г2¯(х) excitons changes in the range 1.44 - 10 eV-cm-1 at temperature variation form 10 K to 230 K (see Fig. 1, C).</p></dc:description> <dc:source>Materials Science and Condensed Matter Physics (Editia 8) 93-93</dc:source> <dc:title>Excitonic polaritons in ZnAs2</dc:title> <dc:type>info:eu-repo/semantics/article</dc:type> </oai_dc:dc>
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