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#REDIRECT [[Selenium]]
Studying physical properties of selenium such as structural, optical, electrical, dielectric properties of selenium films and their behavior to various external agents are of importance from basic research and technical points of view, an issue that still demands further work despite the vast number of literature studies being conducted on different forms of selenium (amorphous, poly-crystalline, and crystalline specimens).
There are several approaches to analyze transmittance data of selenium films, from which one can extract their optical constants and other related topics.<ref>{{Cite journal|last=Jafar|first=Mousa M. Abdul-Gader|last2=Saleh|first2=Mahmoud H.|last3=Ahmad|first3=Mais Jamil A.|last4=Bulos|first4=Basim N.|last5=Al-Daraghmeh|first5=Tariq M.|date=2016-04-01|title=Retrieval of optical constants of undoped amorphous selenium films from an analysis of their normal-incidence transmittance spectra using numeric PUMA method|url=https://link.springer.com/article/10.1007/s10854-015-4156-z|journal=Journal of Materials Science: Materials in Electronics|language=en|volume=27|issue=4|pages=3281–3291|doi=10.1007/s10854-015-4156-z|issn=0957-4522}}</ref>
However, the algebraic method of Swanepoel 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).<ref>{{Cite journal|last=Saleh|first=Mahmoud H.|last2=Ershaidat|first2=Nidal M.|last3=Ahmad|first3=Mais Jamil A.|last4=Bulos|first4=Basim N.|last5=Jafar|first5=Mousa M. Abdul-Gader|date=2017-06-01|title=Evaluation of spectral dispersion of optical constants of a-Se films from their normal-incidence transmittance spectra using Swanepoel algebraic envelope approach|url=https://link.springer.com/article/10.1007/s10043-017-0311-5|journal=Optical Review|language=en|volume=24|issue=3|pages=260–277|doi=10.1007/s10043-017-0311-5|issn=1340-6000}}</ref> <ref>{{Cite web|url=https://www.researchgate.net/publication/272292433_Comprehensive_formulations_forthe_total_normal-incidence_optical_reflectance_and_transmittance_of_thin_films_laid_on_thick_substrates|title=Comprehensive formulations forthe total normal-incidence optical reflectance and transmittance of thin films laid on thick substrates|website=ResearchGate|language=en|access-date=2017-11-06}}</ref>
The following paper deals with conventional curve-fitting of the transmittance data, an approach that depends on the availability of proper dispersion formulas to be inserted in the program.<ref>{{Cite journal|last=Saleh|first=Mahmoud H.|last2=Jafar|first2=Mousa M. Abdul-Gader|last3=Bulos|first3=Basim N.|last4=Al-Daraghmeh|first4=Tariq M. F.|date=2014-10-21|title=Determination of Optical Properties of Undoped Amorphous Selenium (a-Se) Films by Dielectric Modeling of Their Normal-Incidence Transmittance Spectra|url=http://www.ccsenet.org/journal/index.php/apr/article/view/40452|journal=Applied Physics Research|language=en|volume=6|issue=6|pages=10|doi=10.5539/apr.v6n6p10|issn=1916-9647}}</ref>
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. A preliminary thermoanalytical study on Bi-Se composites were conducted via thermogravimetry (TG) and differential thermogravimetry (DTG) experiments using 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, as described in the following paper, 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.<ref>{{Cite journal|last=Ahmad|first=Mais Jamil A.|last2=Jafar|first2=Mousa M. Abdul-Gader|last3=Saleh|first3=Mahmoud H.|last4=Shehadeh|first4=Khawla M.|last5=Telfah|first5=Ahmad|last6=Ziq|first6=Khalil A.|date=2017-09-30|title=Evaluation of Kinetic Parameters and Thermal Stability of Melt-Quenched Bi<sub>x</sub>Se<sub>100−x</sub> Alloys (x ≤7.5 at%) by Non-Isothermal Thermogravimetric Analysis|url=http://www.appmicro.org/journal/view.html?uid=223&&vmd=Full|journal=Applied Microscopy|language=en|volume=47|issue=3|doi=10.9729/AM.2017.47.3.110|issn=2287-5123}}</ref>
A number of studies were carried out on undoped amorphous and crystalline selenium films, in which their structure and electric/dielectric properties/data have been also investigated and analyzed, few of them are listed in the references below and references cited in them.<ref>{{Cite journal|last=Abdul-Gader Jafar|first=M. M.|last2=Nigmatullin|first2=R. R.|date=2001-09-21|title=Identification of a new function model for the AC-impedance of thermally evaporated undoped selenium films using the Eigen-coordinates method|url=http://www.sciencedirect.com/science/article/pii/S004060900101166X|journal=Thin Solid Films|volume=396|issue=1|pages=282–296|doi=10.1016/S0040-6090(01)01166-X}}</ref> <ref>{{Cite journal|last=ABDUL-GADER|first=M. M.|last2=AL-BASHA|first2=MAHMOUD A.|last3=WISHAH|first3=K. A.|date=1998-07-01|title=Temperature dependence of DC conductivity of as-deposited and annealed selenium films|url=http://dx.doi.org/10.1080/002072198134328|journal=International Journal of Electronics|volume=85|issue=1|pages=21–41|doi=10.1080/002072198134328|issn=0020-7217}}</ref> <ref>{{Cite journal|last=I.F.|first=Al-Hamarneh,|last2=B.N.|first2=Bulos,|last3=Abdul-Gader|first3=Jafar, M.M.|title=Effect of isothermal annealing and visible-light illumination on the AC-impedance behavior of undoped selenium thin films|url=http://www.academia.edu/30276102/Effect_of_isothermal_annealing_and_visible-light_illumination_on_the_AC-impedance_behavior_of_undoped_selenium_thin_films|journal=Journal of Non-Crystalline Solids|language=en|volume=355|issue=4-5|issn=0022-3093}}</ref>
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