DC electrical conductivity and switching phenomena of amorphous Te81Ge15Bi4 films

Afifi, M. A.; El-Metwally, E.G.; Hegab, N.A.; Mostfa, M.

doi:10.1016/j.jallcom.2018.06.114

Cited by 8 publications

(12 citation statements)

References 29 publications

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“…It is obvious that ̅ V th decreases exponentially with temperature. This approach is consistent with what has been described in the literature for different amorphous ChGs [11,12,39,66,67]. The thermal energy required to change the filament (material channel) from an amorphous to crystalline condition decreases as the temperature rises, resulting in a significant decrease in ̅…”

Section: Temperature and Thickness Dependence Of The Threshold Voltagesupporting

confidence: 89%

“…The inset of figure 10(b) demonstrates the variation of ̅ V th with film thickness d at RT, revealing that ̅ V th increases linearly with d in the investigated range. Other amorphous chalcogenide glasses showed a similar relation [11,12,39,66].…”

Section: -I V Characteristic Curvesmentioning

confidence: 70%

“…According to Mott and Davis [36], the value of s o ≈ 10 4 (Ω.m) −1 related to the mechanism of hopping in extended states, whereas s o is reduced by factor 10 2 -104 (Ω. m) −1 owing to hopping in the localized states at the band edge. As a result, the acquired ∆ s E and s o values for the examined composition may be ascribed as hopping of charge carriers in the band tail localized states which is dominate in amorphous chalcogenide glasses [12,36,39,65,66]. From our previous work, the values of s RT and ∆ s E in the thickness range (114-597.8 nm) are 5.65 × 10 -12 -2.08 × 10 −13 (Ω.m) −1 and 0.82 ± 0.01 eV, respectively, for TSG ChG films [12].…”

Section: Electrical Properties 331 the DC Conductivitymentioning

confidence: 94%

“…It is obvious that ∆ s E (0.583 ± 0.004 eV) is independent of the film thickness revealing the existence of a single conduction mechanism over the examined range of temperature. Also, s RT and s o decrease with film thickness which may be explained by the increase in the degree of disordered as well as the lattice defects density such as interstitials, vacancies and dislocations that form through thin film deposition [65,66]. According to Mott and Davis [36], the value of s o ≈ 10 4 (Ω.m) −1 related to the mechanism of hopping in extended states, whereas s o is reduced by factor 10 2 -104 (Ω. m) −1 owing to hopping in the localized states at the band edge.…”

Section: Electrical Properties 331 the DC Conductivitymentioning

confidence: 99%

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Non-isothermal crystallization kinetics and memory switching properties of Tl-Se-Ge-Sb chalcogenide semiconductor alloy for thermally stable phase change memory applications

El-Metwally,

Ismail

2023

Phys. Scr.

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Quaternary (Tl20Se70Ge10)0.85Sb0.15 chalcogenide glass was synthesized using melt-quenching and thermal evaporation techniques for bulk and thin film samples, and its amorphous character was confirmed by XRD. Based on different models of non-isothermal crystallization kinetics, the average values of the glass transition E ̅ g and the crystallization E ̅ c activation energies are 121.33 and 82.94 kJ mol−1, respectively. The crystallization mechanism in the examined composition is 2D nucleation growth, according to Avrami exponent n . Thermal parameters of the studied quaternary glass, like fragility F g , fluctuation free volume F FV , reduced glass transition temperature T rg , thermal stability SP and glass formation ability GFA were investigated and indicated that the (Tl20Se70Ge10)0.85Sb0.15 ChG exhibits a good ability of glass formation and thermal stability. The obtained results of the dc electrical conductivity σ dc are found to increase with temperature and decrease with film thickness. The electrical conduction activation energy ∆ E σ (0.583 ± 0.004 eV) is thickness independent and the predominant conduction mechanism is the hopping of charge carriers in the band tail localized states. The ( I – V ) curves of (Tl20Se70Ge10)0.85Sb0.15 chalcogenide glass film samples were analyzed and shown to be appropriate for a memory switch. The mean value of the threshold voltage V ̅ th decreases exponentially as temperature increases, whereas it increases linearly as film thickness increases. The values of threshold voltage ε th and threshold resistance ∆ E R activation energies are 0.282 ± 0.003 and 0.521 ± 0.004 eV, respectively. The obtained switching characteristics data were discussed in view of the electrothermal model motivated by current channel Joule heating. These findings highlight the suitability of the investigated composition for various optoelectronic applications, such as memory switching devices, optical data storage, phase-change memories and optical fibres sensing devices.

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Section: Temperature and Thickness Dependence Of The Threshold Voltagesupporting

confidence: 89%

Section: -I V Characteristic Curvesmentioning

confidence: 70%

Section: Electrical Properties 331 the DC Conductivitymentioning

confidence: 94%

Section: Electrical Properties 331 the DC Conductivitymentioning

confidence: 99%

See 2 more Smart Citations

Non-isothermal crystallization kinetics and memory switching properties of Tl-Se-Ge-Sb chalcogenide semiconductor alloy for thermally stable phase change memory applications

El-Metwally,

Ismail

2023

Phys. Scr.

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“…Chalcogenide alloys, consisting of chalcogen elements (S, Se and Te) or these elements as major constituents, are gathering attention from researchers and technological world because of their wide range of applications. Chalcogenide alloys are important materials for technologically important devices, such as optical data storage [1, 2], phase change random access memory [3, 4], near-infrared transmission window [5, 6], electrical switching [7, 8], optical fiber [9], solar cell [10], xerography [11] etc.…”

Section: Introductionmentioning

confidence: 99%

Composition dependent structural phase transition and optical band gap tuning in InSe thin films

Singh

et al. 2019

Heliyon

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Bulk alloys of InxSe100-x (x = 5, 10, 20, 30, 40 and 50) are prepared using melt quenching technique. Thin films having thickness ~750 nm of these prepared bulk alloys are fabricated using thermal evaporation technique on glass substrate. The as-deposited InxSe100-x thin films with x ≤ 40 are amorphous and In50Se50 thin film is crystalline in nature verified from X-ray diffraction (XRD). The change in morphology of deposited thin films with indium content also verifies structural phase transition and found that the phase transition started with x = 40 which is not detected in XRD pattern. The drastic change in transmission is found with 50% indium content. In50Se50 thin film has less than 30% transmission whereas other films are highly transparent. Optical band gap is calculated using Tauc's plot and decrease in optical band gap is observed with indium content. The variation of optical band gap from 1.88 eV to 1.12 eV is achieved with indium content of 5%–50%. The structural transition and change in optical band gap depict that InSe thin films are potential candidates in various technological applications.

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The ac conduction mechanism and dielectric relaxation behavior of amorphous Te81Ge15Bi4 chalcogenide glass thin films

El-Metwally

Hegab

Mostfa

2022

J Mater Sci: Mater Electron

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Various chalcogenide amorphous films of Te81Ge15Bi4 in the range (143–721 nm) were synthesized using the thermal evaporation technique. The ac electrical conductivity $${\sigma }_{ac}\left(\omega \right)$$ σ ac ω and dielectric measurements were examined for the studied films over the temperature and frequency ranges of (303–393 K) and (100 Hz–1 MHz), respectively. The obtained results of ac conductivity $${\sigma }_{ac}\left(\omega \right)$$ σ ac ω are temperature dependent and follow the relation $${\sigma }_{ac}\left(\omega \right)\propto {\omega }^{s}$$ σ ac ω ∝ ω s , where the frequency exponent $$s$$ s decrements with temperature through the examined range. These results of $${\sigma }_{ac}\left(\omega \right)$$ σ ac ω and $$s$$ s are explained based on the correlated barrier hopping CBH model. Values of ac activation energy $$\Delta {E}_{\sigma }\left(\omega \right)$$ Δ E σ ω show thickness independence and decrease from 0.270 to 0.144 eV as the frequency increases. The estimated maximum barrier height $${W}_{M}$$ W M values decrement with temperature in the considered frequency range. The density of localized states near the Fermi level $$N\left({E}_{F}\right)$$ N E F increases with increasing temperature and frequency. The dielectric constant $${\varepsilon }_{1}(\omega )$$ ε 1 ( ω ) and loss $${\varepsilon }_{2}(\omega )$$ ε 2 ( ω ) were found to increment with temperature and decrement with frequency. The obtained results indicate that $${\sigma }_{ac}\left(\omega \right)$$ σ ac ω , $$N\left({E}_{F}\right)$$ N E F , $${\varepsilon }_{1}\left(\omega \right)$$ ε 1 ω and $${\varepsilon }_{2}\left(\omega \right)$$ ε 2 ω are enhanced by decreasing the thickness of the film sample in the investigated ranges of temperature and frequency. The real $${M}_{1}(\omega )$$ M 1 ( ω ) and imaginary $${M}_{2}(\omega )$$ M 2 ( ω ) parts of the electric modulus were studied for the films under test, and the value of the activation energy for relaxation $$\Delta {E}_{r}$$ Δ E r (0.143 ± 0.002 eV) is thickness independent in the investigated range.

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DC electrical conductivity and switching phenomena of amorphous Te81Ge15Bi4 films

Cited by 8 publications

References 29 publications

Non-isothermal crystallization kinetics and memory switching properties of Tl-Se-Ge-Sb chalcogenide semiconductor alloy for thermally stable phase change memory applications

Non-isothermal crystallization kinetics and memory switching properties of Tl-Se-Ge-Sb chalcogenide semiconductor alloy for thermally stable phase change memory applications

Composition dependent structural phase transition and optical band gap tuning in InSe thin films

The ac conduction mechanism and dielectric relaxation behavior of amorphous Te81Ge15Bi4 chalcogenide glass thin films

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