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Optical properties of selenium

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Selenium powder is an amorphous, brick-red powder that may become black upon exposure to air,[1] while vitreous ingots and films/crystals are black,[2] with physical properties divided into structural, optical, electrical, and dielectric. Its behavior to various external agents are of importance from basic research and technical points of view.

Black, glassy amorphous, and red amorphous selenium

Optical properties

File:Envelope Method.tif
The as-measured normal-incidence transmission spectra of a-, a-, and a- samples (open symbols are measured data) and substrate (black solid curve). The inset shows constructed maxima and minima envelope curves for the a-Se1000 sample transmittance

There are several approaches to analyze transmittance data of selenium films, from which one can extract their optical constants and other related topics.[3] However, the algebraic method of Swanepoel envelope method (EM) seems to be trustful and need no dispersion relations in prior, but is limited to transmittance spectra that display a number of peaks (maxima and minima).[4] However, EM method has a further limitation that is only of good validity in a wide spectral region in the quasi-transparency [5][6] Conventional curve-fitting of the transmittance data, an approach that depends on the availability of proper dispersion formulas to be inserted in the program, usually yield multi-solutions of the problem (that is, local solutions, from which different, sometimes unrealistic, fitting parameters and care should be taken to choose the correct results, and only a global solution of the problem gives physically-meaningful results.[7]

Thermoanalytical properties

Stoichiometric films of selenium-based alloys such as those of Bi-Se and Bi-Te composites are of technical importance for applications in memory switch devices. Thermoanalytical studies often give information about their stoichiometry, melting/boiling points and kinetic reactions responsible for their decomposition and crystallization. Thermoanalytical study on Bi-Se composites using thermogravimetry (TG) and differential thermogravimetry (DTG) experiments with a single heating rate and analyzing the measured non-isothermal TG and DTG curves via model-based kinetic reaction formulas of original Coats-Redfern (CR) and Achar-Brindley-Sharp (ABS) equations yields promising results on the nature of kinetic reaction models operational in such systems.[8] , though it is always preferable to analyze such TG and DTG data on the basis of model-free kinetic reaction formulations and several heating rates, in addition to performing differential scanning calorimetric (DSC) and differential temperature analysis (DTA) which usually give more information on crystallinity contents as well as important thermal properties.[9]

Electric and dielectric properties

Investigating the electrical and dielectric properties of undoped amorphous and crystalline selenium films, as well as Se-based composites often give informative results and lead to further understanding of the electrical behavior and conduction/dispersion processes prevailing in the sample [10] [11] [12] that are important in the design and manufacturing of electronic devices based on these films.[13][14][15]

See also

References

  1. ^ GOV, NOAA Office of Response and Restoration, US. "SELENIUM POWDER | CAMEO Chemicals | NOAA". cameochemicals.noaa.gov. Retrieved 2017-11-06.{{cite web}}: CS1 maint: multiple names: authors list (link)
  2. ^ O’Bannon, Loran S. Dictionary of Ceramic Science and Engineering | SpringerLink. doi:10.1007/978-1-4613-2655-7.
  3. ^ Jafar, Mousa M. Abdul-Gader; Saleh, Mahmoud H.; Ahmad, Mais Jamil A.; Bulos, Basim N.; Al-Daraghmeh, Tariq M. (2016-04-01). "Retrieval of optical constants of undoped amorphous selenium films from an analysis of their normal-incidence transmittance spectra using numeric PUMA method". Journal of Materials Science: Materials in Electronics. 27 (4): 3281–3291. doi:10.1007/s10854-015-4156-z. ISSN 0957-4522.
  4. ^ Saleh, Mahmoud H.; Ershaidat, Nidal M.; Ahmad, Mais Jamil A.; Bulos, Basim N.; Jafar, Mousa M. Abdul-Gader (2017-06-01). "Evaluation of spectral dispersion of optical constants of a-Se films from their normal-incidence transmittance spectra using Swanepoel algebraic envelope approach". Optical Review. 24 (3): 260–277. doi:10.1007/s10043-017-0311-5. ISSN 1340-6000.
  5. ^ "Comprehensive formulations forthe total normal-incidence optical reflectance and transmittance of thin films laid on thick substrates". ResearchGate. Retrieved 2017-11-06.
  6. ^ Minkov, D.A.; Gavrilov, G.M.; Angelov, G.V.; Moreno, J.M.D.; Vazquez, C.G.; Ruano, S.M.F.; Marquez, E. "Optimisation of the envelope method for characterisation of optical thin film on substrate specimens from their normal incidence transmittance spectrum". Thin Solid Films. doi:10.1016/j.tsf.2017.11.003.
  7. ^ Saleh, Mahmoud H.; Jafar, Mousa M. Abdul-Gader; Bulos, Basim N.; Al-Daraghmeh, Tariq M. F. (2014-10-21). "Determination of Optical Properties of Undoped Amorphous Selenium (a-Se) Films by Dielectric Modeling of Their Normal-Incidence Transmittance Spectra". Applied Physics Research. 6 (6): 10. doi:10.5539/apr.v6n6p10. ISSN 1916-9647.
  8. ^ Ahmad, Mais Jamil A.; Jafar, Mousa M. Abdul-Gader; Saleh, Mahmoud H.; Shehadeh, Khawla M.; Telfah, Ahmad; Ziq, Khalil A. (2017-09-30). "Evaluation of Kinetic Parameters and Thermal Stability of Melt-Quenched BixSe100−x Alloys (x ≤7.5 at%) by Non-Isothermal Thermogravimetric Analysis". Applied Microscopy. 47 (3). doi:10.9729/AM.2017.47.3.110. ISSN 2287-5123.
  9. ^ Introduction to Thermal Analysis - Techniques and | Michael Ewart Brown | Springer.
  10. ^ Abdul-Gader Jafar, M. M.; Nigmatullin, R. R. (2001-09-21). "Identification of a new function model for the AC-impedance of thermally evaporated undoped selenium films using the Eigen-coordinates method". Thin Solid Films. 396 (1): 282–296. doi:10.1016/S0040-6090(01)01166-X.
  11. ^ ABDUL-GADER, M. M.; AL-BASHA, MAHMOUD A.; WISHAH, K. A. (1998-07-01). "Temperature dependence of DC conductivity of as-deposited and annealed selenium films". International Journal of Electronics. 85 (1): 21–41. doi:10.1080/002072198134328. ISSN 0020-7217.
  12. ^ I.F., Al-Hamarneh,; B.N., Bulos,; Abdul-Gader, Jafar, M.M. "Effect of isothermal annealing and visible-light illumination on the AC-impedance behavior of undoped selenium thin films". Journal of Non-Crystalline Solids. 355 (4–5). ISSN 0022-3093.{{cite journal}}: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link)
  13. ^ "Wiley: Physics of Semiconductor Devices, 3rd Edition - Simon M. Sze, Kwok K. Ng". eu.wiley.com. Retrieved 2017-11-08.
  14. ^ Broadband Dielectric Spectroscopy | Friedrich Kremer | Springer.
  15. ^ K.), Jonscher, A. K. (Andrzej (1983). Dielectric relaxation in solids. London: Chelsea Dielectrics Press. ISBN 0950871109. OCLC 10084589.{{cite book}}: CS1 maint: multiple names: authors list (link)
 

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