Structural and optical properties of CdTe thin film: A detailed investigation using optical absorption, XRD, and Raman spectroscopies

Nassar, Zaher M.; Yükselici, M. H.; Bozkurt, Asuman Aşıkoğlu

doi:10.1002/pssb.201552433

Cited by 19 publications

(8 citation statements)

References 47 publications

(81 reference statements)

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“…46 For OCNT, the peaks at 2θ = 25.9 and 42.8 from (002) and (100) planes of the hexagonal graphite structure. 47 For the identification of CdTe nanocrystals, some small peaks at 2θ = 24.2 , 40.2 , and 45.3 from (111), (220), and (311) planes of CdTe nanocrystals 48,49 were observed in the prepared inorganics and membranes. The XRD curves of inorganics and membranes with bmimPF 6 exhibited broadening and reduction in the intensity of diffraction peaks.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

Pan

Jia

Duan

et al. 2019

J of Applied Polymer Sci

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The widespread participation of polymers in the membrane preparation has been considering to be critical for the development of proton exchange membranes (PEMs). For the polymers without functional groups to conduct protons, the introduction of proton conduction carriers with the formation of composite membranes is an effective strategy to prepare PEMs with the outstanding proton conductivity. However, there remains a potential risk of the components leaking from composite membranes due to the lack of the interaction force. Here, the composite of carbon nanotube oxide (OCNT) assembling with cadmium telluride (CdTe) and 1‐butyl‐3‐methylimidazolium hexafluorophosphate (bmimPF6) was introduced into the system of phosphoric acid (PA) doping poly(vinylidene fluoride) (PVDF) with the formation of PVDF/OCNT‐CdTe‐bmimPF6/85%PA membranes. PA molecules are anchored by the inorganics of OCNT‐CdTe‐bmimPF6 and are stabilized in membranes. The high and stable proton conductivity values at the elevated temperature are obtained comparing the reported PVDF/bmimPF6/PA membranes. Specifically, the proton conductivity value reached 1.28 × 10−1 S/cm at 160 °C and the value is stable 1.70 × 10−2 S/cm at 120 °C lasting for 350 h. The fine stability in components could make the membranes extricate from the predicament of proton conductivity decline exceeding 120 °C under anhydrous conditions in PVDF/bmimPF6/PA membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48833.

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Section: X-ray Diffractionmentioning

confidence: 99%

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

Pan

Jia

Duan

et al. 2019

J of Applied Polymer Sci

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“…An amorphous nature was observed for the as-deposited (nonirradiated) as shown in Fig. 1 a, the broad peak between 20° -30° which is usually observed in glass's x-ray diffraction pattern [27], that could be related to substrate's scattering because of the small CdTe thickness (50 nm) [28]. The x-ray pattern for the irradiated samples, shows an increase in the crystalline nature due to irradiation; the preferred orientation peak at 2θ = 23.7º confirms the creation of cubic zinc blend structure [29].…”

Section: Resultsmentioning

confidence: 79%

The γ-irradiation Effect on the Optical Properties of CdTe Thin Films Deposited by Thermal Evaporation Technique

Afaneh

Okasha

Hamam

et al. 2018

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CdTe thin films of 50 nm thickness have been deposited on glass substrates by thermal vacuum evaporation technique and the γ-irradiation effect on their optical properties has been investigated. Transmittance and reflectance have been measured at normal incidence, in the visible region from 400 to 700 nm, and were used to evaluate the optical parameters and the band gap energy for CdTe thin films before and after γ-irradiation. Structure and surface morphology before and after γirradiation were investigated using X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) respectively. XRD pattern of the as-deposited CdTe film shows an amorphous nature. Crystalline structure was observed to improve when samples were exposed to γ-irradiation at doses from 40-120 kGy in the (111) plane of the cubic zincblende structure. SEM shows a change in the surface morphology of CdTe films as a consequence of γ-irradiation compared to as-deposited sample. The optical properties such as refractive index, extinction coefficient, dielectric constant were found to decrease with the increase of the dose of γ-irradiation. Energy band gap was found to decrease from 2.47 eV for the as-deposited down to 2.20 eV for 120 kGy (blue shift compared to bulk CdTe), that was attributed to the small thin film thickness.

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“…The charge carriers that are confined within the potential barriers of the non‐isolated particles (the particles which are close to each other) are subjected to insignificant quantum size effect due to the limited potential barrier value “between the particles,” while those confined within the isolated particles are subjected to considerably quantum size effect . Quantum size effect is related to exciton Bohr radius a B ; for grain sizes R < a B (strong confinement) splitting in the energy levels is observed which causes larger optical bandgap energy, for grains of radii R ∼ a B the quantum size effect is intermediate, and for R > a B the confinement is weak.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Strain and Grain Size on Phonon and Electron Confinements in TiO₂ Thin Films

Nassar

Yükselici

2018

Physica Status Solidi (b)

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Titanium dioxide (TiO 2 ) powder in anatase phase is thermally evaporated by physical vapor deposition (PVD) on glass substrates. Different-thickness TiO 2 thin films are deposited on glass slides. The samples are then optically and structurally investigated using optical absorption (ABS) and Raman scattering (RS). Optical absorption spectroscopy shows that Urbach energy (E U ) related to the width of the long-wavelength tail decreased from 212 to 176 meV as the film thickness increased from 143 to 221 nm, respectively. The grain size, which depends on thickness of the film, and the grain size distribution are evaluated by fitting the absorption coefficient α experimental data to a model of α as a function of energy E. Absorption edge energy (E R ) is also calculated, it decreases by 165 meV as the film thickness increases from 143 to 221 nm. The energies of band gap transitions are also determined from the observed data of absorption. There are two types of transitions, i.e., direct and indirect transitions, in the TiO 2 compound. The phonon confinement model is used to interpret the size effect in Raman scattering. Relative to the Raman active E g mode of bulk TiO 2 crystal, a size-dependent blue shift is noticed in the Raman bands for the first and second E g modes (E 1 ð Þ g : %144 cm À1 and E 2 ð Þ g : 197 cm À1 , respectively). In this study, the results of Raman scattering and optical absorption are combined together in order to investigate the grain size effect, structural disorder, and thickness-dependent strain. In ABS spectroscopy, it is noticed that (at certain wavelength) the intensity of the transmitted light for the thinner sample is higher than that for the thicker one, which is compatible with the relation I ¼ I 0 e Àαt , where α is the absorption coefficient and t is the thickness.

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Structural and optical properties of CdTe thin film: A detailed investigation using optical absorption, XRD, and Raman spectroscopies

Cited by 19 publications

References 47 publications

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

The γ-irradiation Effect on the Optical Properties of CdTe Thin Films Deposited by Thermal Evaporation Technique

The Effect of Strain and Grain Size on Phonon and Electron Confinements in TiO₂ Thin Films

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Structural and optical properties of CdTe thin film: A detailed investigation using optical absorption, XRD, and Raman spectroscopies

Cited by 19 publications

References 47 publications

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

Investigation on carbon nanotube oxide for anhydrous proton exchange membranes application

The γ-irradiation Effect on the Optical Properties of CdTe Thin Films Deposited by Thermal Evaporation Technique

The Effect of Strain and Grain Size on Phonon and Electron Confinements in TiO2 Thin Films

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The Effect of Strain and Grain Size on Phonon and Electron Confinements in TiO₂ Thin Films