Retrieval of optical constants of undoped amorphous selenium films from an analysis of their normal-incidence transmittance spectra using numeric PUMA method

Jafar, Mousa M. Abdul-Gader; Saleh, Mahmoud H.; Ahmad, Mais Jamil A.; Bulos, Basim N.; Al-Daraghmeh, Tariq M.

doi:10.1007/s10854-015-4156-z

Cited by 12 publications

(6 citation statements)

References 39 publications

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“…4 A4 sample transmittance (120 min) using the envelope method smaller nuclei. This observation is in line with the results obtained by Hanaor and Sorrell [27]. Films with different thicknesses show color changes.…”

Section: Resultssupporting

confidence: 93%

“…This solution must contain the smallest standard deviation between the theoretical and measured values so that the results are optimized. This method proves to be extremely useful and reliable for estimating film thickness when using four-digit transmission data [27]. The great challenge of this computational method is to provide precise values of thickness in analyzes of optical transmittance spectra, mainly when the samples are considerably thin films and with a high value of optical absorption coefficient [28].…”

Section: Introductionmentioning

confidence: 99%

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Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Sobrinho¹,

Neto

Lima

et al. 2020

Braz J Phys

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The study of thin films with properties that meet specific needs and improve people's quality of life has been the focus of many researchers. However, knowing and controlling the production techniques of these films have been a challenge for the industry of optical-electronic devices, functional coatings, and energy conservation. The thickness of thin films is a parameter that influences the optical and electrical characteristics of these materials, thus being one of the most important information in the plasma deposition process. Because of the need for precision in measuring the thickness of thin transparent films, this work proposes to evaluate the Swanepoel methods (envelope) and the PUMA, computational method, from optical transmittance curves and compare them with the measurements directly made by microscopy. Scanning electronics for thin films of TiO 2 deposited by magnetron sputtering in different conditions. The results of this study showed that the PUMA method is capable of calculating film thicknesses of a few hundred nanometers and with few interference fringes. The PUMA method showed convergence with high precision for films produced with 30 and 60 min of treatment and a difference of 17% for films with 120 min of deposition concerning the measurements made by microscopy.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Sobrinho¹,

Neto

Lima

et al. 2020

Braz J Phys

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“…Selenium, as well as other elements in the main group VIA, has been extensively studied in the field of materials science owing to its unique properties such as high photoconductivity, nonlinear optical response, large piezoelectricity and thermoelectric effect (Jafar et al, 2016;Saleh et al, 2017;Dieulesaint & Royer, 1982;Henkels & Maczuk, 1953). In addition, its intriguing inner structural behavior under high pressure which leads to a rich sequence of pressure-induced phases attracts numerous studies focusing on selenium under high pressure (Akahama et al, 2021(Akahama et al, , 1993(Akahama et al, , 1992aBrazhkin et al, 1992;Kru ¨ger & Holzapfel, 1992;Nishikawa et al, 1996Nishikawa et al, , 1993Pal et al, 2015;Parthasarathy & Holzapfel, 1988;Bandyopadhyay & Ming, 1996;Dai et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Negative linear compressibility in Se at ultra-high pressure above 120 GPa

Yuan¹,

Wang²,

Zhu³

et al. 2022

IUCrJ

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A series of in situ synchrotron X-ray diffraction (XRD) measurements were carried out, combined with first-principles calculations, to study structural phase transitions of selenium at high pressures and room temperature. Several phase transitions were observed, among which an isostructural phase transition was found at around 120 GPa for the first time. Evolved from the rhombohedral (space group R 3 m) structure (Se-V), the new phase (Se-V′) exhibited an interesting increase of lattice parameter a at pressures from 120 to 148 GPa, known as negative linear compressibility (NLC). The discovery of NLC behavior observed in this work is mainly attributed to the accuracy and fine steps controlled by the membrane system for in situ XRD data collected with an exposure time of 0.5 s. After 140 GPa, a body-centered cubic (b.c.c.) structure Se-VI (space group Im 3 m) was formed, which remains stable up to 210 GPa, the highest pressure achieved in this study. The bulk moduli of phases Se-V, Se-V′ and Se-VI were estimated to be 83 ± 2, 321 ± 2 and 266 ± 7 GPa, respectively, according to the P–V curve fit by the third-order Birch–Murnaghan equation of state. The Se-V′ phase shows a bulk modulus almost 4 times larger than that of the Se-V phase, which is mainly due to the effect of its NLC. NLC in a higher pressure range is always more significant in terms of fundamental mechanism and new materials discovery, yet it has barely been reported at pressures above 100 GPa. This will hopefully inspire future studies on potential NLC behaviors in other materials at ultra-high pressure.

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“…Undoped amorphous selenium (α -Se) is a twofoldcoordinated glassy p-type semiconductor with high dark electrical resistivity (~10 12 Ω cm at 300 K) and bandgap energy E g as large as 2 eV at 300 K (Bettsteller et al, 1993;Jafar et al, 2016;Mott & Davis, 1979;Saleh et al, 2017). Yet, undoped α-Se has minor photosensitivity for electromagnetic radiation of red wavelengths and larger (Bettsteller et al, 1993;Jafar et al, 2016;Mott & Davis, 1979).…”

Section: Introductionmentioning

confidence: 99%

“…Yet, undoped α-Se has minor photosensitivity for electromagnetic radiation of red wavelengths and larger (Bettsteller et al, 1993;Jafar et al, 2016;Mott & Davis, 1979). In addition, unwanted thermal-/photo-crystallization features of pure a-Se at low ambient temperatures, due to its low glasstransition temperature T G (around 45°C), make it of unstable structure and short working lifetime arising from ageing effects and thermal instability that lead to adverse changes in its physical properties (Innami & Adachi, 1999;Kasap et al, 1990;Saleh et al, 2017;Tonchev & Kasap, 2002).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Kinetic Parameters and Thermal Stability of Melt-Quenched Bi_xSe_100-xAlloys (x ≤7.5 at%) by Non-Isothermal Thermogravimetric Analysis

Ahmad

Jafar

Saleh

et al. 2017

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Non-isothermal thermogravimetry (TG) measurements on melt-quenched Bi x Se 100-x specimens (x=0, 2.5, 7.5 at%) were made at a heating rate β=10°C/min in the range T=35°C~950°C. The as-measured TG curves confirm that Bi x Se 100-x samples were thermally stable with minor loss at T≲400°C and mass loss starts to decrease up to 600°C, beyond which trivial mass loss was observed. These TG curves were used to estimate molar (Se/Bi)-ratios of Bi x Se 100-x samples, which were not in accordance with initial composition. Shaping features of conversion curves α(T)-T of Bi x Se 100-x samples combined with a reliable flow chart were used to reduce kinetic mechanisms that would have caused their thermal mass loss to few nth-order reaction models of the form f [α(T)][1-α(T)]n (n=1/2, 2/3, and 1). The constructed α(T)-T and (dα(T)/dT)-T curves were analyzed using Coats-Redfern (CR) and Achar-Brindley-Sharp (ABS) kinetic formulas on basis of these model functions, but the linearity of attained plots were good in a limited α(T)-region. The applicability of CR and ABS methods, with model function of kinetic reaction mechanism R0 (n=0), was notable as they gave best linear fits over much broader α(T)-range.

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Retrieval of optical constants of undoped amorphous selenium films from an analysis of their normal-incidence transmittance spectra using numeric PUMA method

Cited by 12 publications

References 39 publications

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Negative linear compressibility in Se at ultra-high pressure above 120 GPa

Evaluation of Kinetic Parameters and Thermal Stability of Melt-Quenched Bi_xSe_100-xAlloys (x ≤7.5 at%) by Non-Isothermal Thermogravimetric Analysis

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Retrieval of optical constants of undoped amorphous selenium films from an analysis of their normal-incidence transmittance spectra using numeric PUMA method

Cited by 12 publications

References 39 publications

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Optical-Electrical Properties and Thickness Analysis of TiO2 Thin Films Obtained by Magnetron Sputtering

Negative linear compressibility in Se at ultra-high pressure above 120 GPa

Evaluation of Kinetic Parameters and Thermal Stability of Melt-Quenched BixSe100-xAlloys (x ≤7.5 at%) by Non-Isothermal Thermogravimetric Analysis

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Evaluation of Kinetic Parameters and Thermal Stability of Melt-Quenched Bi_xSe_100-xAlloys (x ≤7.5 at%) by Non-Isothermal Thermogravimetric Analysis