Scrutiny of structural disorder using Raman spectra and Tauc parameter in GeTe<sub>2</sub> thin films

Kumar, Raju; Mousa, Hussein A.; Lekha, P. Chithra; Mahmoud, Saleh T.; Qamhieh, Naser

doi:10.1088/1742-6596/869/1/012018

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…30 This measurement correlates optical properties to the electronic structure of the materials, being sensitive to small structural disturbances. 31 The sintering process at 1000°C shows a higher average value of Eg among materials sintered in the microwave furnace (5, 10, and 15 minutes) and conventional furnace (60 min), as shown in Figure 11, indicating an increase in local disorder (short-length), 32 which can be confirmed by the Raman data from Figure 10. The same effect of order/ disorder alternation in phase transition associated with Eg has already been observed by Guin et al (2016).…”

Section: Resultsmentioning

confidence: 64%

“…To analyze the evolution of the material due to the thermal effect and their reflections in the optical gap, the parameters Tauc or Eg , applied to determine the optical bandgap in semiconductors, were used 30 . This measurement correlates optical properties to the electronic structure of the materials, being sensitive to small structural disturbances 31 …”

Section: Resultsmentioning

confidence: 99%

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Microwave hybrid fast sintering of red clay ceramics

Lyra

Santos

Pallone

et al. 2021

Int J Applied Ceramic Tech

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The red clay ceramic industry is of great importance for the Brazilian civil construction sector, accounting for approximately 7000 companies that generate 290 000 jobs, with almost US $5 billion in annual sales, and among its main products are tiles, blocks, and tubes. Most of these companies use wood and natural gas to fuel their furnaces, resulting in high CO 2 emissions. 1 Considering the high amount of greenhouse gases generated by this industry, 1 studies have investigated clean technologies for the production of red ceramics, looking for a sustainable material with better physical and mechanical properties and a more refined microstructure, 2 in addition to lower energy consumption. 3 One option to reduce energy consumption and environmental impacts while optimizing the mechanical properties of ceramics is to use unconventional methods, for instance, microwave furnace sintering. However, there is still little research about microwave sintering in traditional ceramics, for example, porcelain and red ceramics. 4 Some studies about porcelain microwave sintering have shown high viability in this process in traditional ceramics. Fernandes et al. (2013) 4 showed that the hybrid sintering of porcelain glazed in microwaves provided physical and

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Section: Resultsmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Microwave hybrid fast sintering of red clay ceramics

Lyra

Santos

Pallone

et al. 2021

Int J Applied Ceramic Tech

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“…[26] It is mentioned that damped motion of charge carriers which are accelerated in the direction of the photon electric field parallel to the film surface and propagating at normal incidence can result in the free carrier absorption phenomena in the films. [30] To gain information about the nature of the optical transitions in the films Tauc's equation ( (𝛼E) n = B n (E − E g ), B is Tauc parameter) was employed. [25][26][27] The fitting of the equation is illustrated in Figure 2d.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Growth and Characterization of Lanthanum Germanide Thin Films by the Thermal Evaporation Technique

Alkhamisi

Qasrawi

Khanfar

2023

Cryst. Res. Technol.

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Lanthanum germanide (La6Ge) thin films are successfully fabricated using the thermal evaporation technique under a vacuum pressure of 10−5 mbar. The resulting films display an orthorhombic structure, characterized by lattice parameters of a = 8.725 Å, b = 8.063 Å, and c = 5.569 Å. Optical analysis of the La6Ge thin films reveal their high transparency, with an energy bandgap of 3.75±0.04 eV. The bandgap exhibits indirect allowed transitions and featured energy band tails with widths measuring (1.64±0.14) eV. In addition, dielectric dispersion analyses indicate the presence of two dominant dielectric resonance peaks centered at 3.15 and 2.08 eV. Moreover, the La6Ge films demonstrate a terahertz (THz) cutoff frequency of 1.0 THz when illuminated with infrared and visible light. This cutoff frequency increases to 45.6 THz in the ultraviolet range. Furthermore, by utilizing the Drude–Lorentz method, the investigation of optical conductivity parameters reveals that the lanthanum germanide optical filters can achieve free hole density and drift mobility values of 14.44 cm2 V−1 s−1 and 2.8×1018 cm−3, respectively, under infrared light irradiation. The outstanding optical and dielectric properties exhibited by the La6Ge thin films make them excellent candidates for highly transparent optical filters suitable for terahertz technology.

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“…In addition, a peak at around 238 cm −1 may originate from ionized Te dimers (Te 2 − color center) or Te 2 or Te n clusters. [34][35][36] Another possible identification of this peak is TeO 3 2− (specifically the OH units in the hydrogen bonding of (TeO 3 ) 2− units [37] ) at the expense of those with higher wavenumbers, indicating that the glass network is progressively cleaved. A few other studies state that this peak may also be related to the formation of WO 3 crystals, [38,39] rhombohedral-TeO 3 , [40] or β-TeO 2 crystals.…”

Section: Formation Of T-te On Tellurite Glass Surface: From a Single ...mentioning

confidence: 99%

Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation

et al. 2023

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The formation of elemental trigonal tellurium (t‐Te) on tellurite glass surfaces exposed to femtosecond laser pulses is discussed. Specifically, the underlying elemental crystallization phenomenon is investigated by altering laser parameters in common tellurite glass compositions under various ambient conditions. Elemental crystallization of t‐Te by a single femtosecond laser pulse is unveiled by high‐resolution imaging and analysis. The thermal diffusion model reveals the absence of lattice melting upon a single laser pulse, highlighting the complexity of the phase transformation. The typical cross‐section displays three different crystal configurations over its depth, in which the overall thickness increases with each subsequent pulse. The effect of various controlled atmospheres shows the suppressing nature of the elemental crystallization, whereas the substrate temperature shows no significant impact on the nucleation of t‐Te nanocrystals. This research gives new insight into the elemental crystallization of glass upon femtosecond laser irradiation and shows the potential to fabricate functional transparent electronic micro/nanodevices.

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Scrutiny of structural disorder using Raman spectra and Tauc parameter in GeTe₂ thin films

Cited by 6 publications

References 11 publications

Microwave hybrid fast sintering of red clay ceramics

Microwave hybrid fast sintering of red clay ceramics

Growth and Characterization of Lanthanum Germanide Thin Films by the Thermal Evaporation Technique

Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation

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Scrutiny of structural disorder using Raman spectra and Tauc parameter in GeTe2 thin films

Cited by 6 publications

References 11 publications

Microwave hybrid fast sintering of red clay ceramics

Microwave hybrid fast sintering of red clay ceramics

Growth and Characterization of Lanthanum Germanide Thin Films by the Thermal Evaporation Technique

Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation

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Scrutiny of structural disorder using Raman spectra and Tauc parameter in GeTe₂ thin films