Variable range hopping conduction in n-CdSe samples at very low temperature

Errai, M.; kaaouachi, A. El; Idrissi, Hassan El

doi:10.1088/1674-4926/36/12/122001

Cited by 10 publications

(5 citation statements)

References 16 publications

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“…The decrease in conductivity with a further increase in Zn was achieved because Zn introduces more additional scattering centers at the grain boundary which trap and scatter the conduction electrons and increases the height of the Schottky barriers, which therefore delay carriers' transport OE11 . The electrical transport in the insulating three-dimensional n-type CdSe samples was reported by Errai et al (2015) at low temperatures and found that the exponents are very close to 0.25 for all the samples. This shows that the electrical conductivity follows the hopping law and also indicates the existence of the regime Mott VRH without electron-electron interaction in the entire temperature range OE14 .…”

Section: Resultsmentioning

confidence: 81%

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

et al. 2017

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Cd1−xZnxS nanoparticles were grown on pre-cleaned glass substrates using microwave-assisted chemical bath deposition technique. Nanoparticles obtained by this method were smooth, uniform, good adherent, brownish yellow in color where the brightness of the yellow color nature decreases with increasing Zn2+ content. The elemental composition analysis confirmed that the nanoparticles comprise of Cd2+, Zn2+ and S2−. Scanning electron microscope images confirmed the surface uniformity of the Cd1−xZnxS nanoparticles devoid of any void, pinhole or cracks and covered the substrate well. The particle size also decreases with increasing Zn ion content. X-ray diffraction (XRD) indicates the hexagonal structure (002) without phase transition. The grain size decreases from 36.45 to 9.60 nm, dislocation density increases from 0.000745 to 0.01085 Line2/m2 and lattice parameter decreased from 6.868 to 6.155 nm with increasing Zn2+ content. The best transmittance of about 95% was achieved for x = 1.0. The nanoparticles showed reduction in the absorbance as Zn ion content increased. Four point probe revealed that the electrical resistivity increased from 1.51 × 1010 to while electrical conductivity decreases from 6.62 × 10−11 to with increasing Zn2+ content. The other electrical properties such as sheet resistance increased from 1.52 × 108 to , charge carrier mobility decreased from 0.777 to 0.0105 cm2/(V s) and charge carrier density increased from 1.06 × 1012 to 3.95 × 1012 cm−3.

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Section: Resultsmentioning

confidence: 81%

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

et al. 2017

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“…It is difficult, therefore, to determine which of the hopping mechanisms is observed. Such a problem is commonly perceived for other materials and requires additional analysis [ 44 ]. In our case, we decided to use the M-VRH model due to the higher correlation coefficients 0.998 instead of 0.987 achieved for this model.…”

Section: Resultsmentioning

confidence: 99%

“…It is difficult, therefore, to determine which of the hopping mechanisms is observed. Such a problem is commonly perceived for other materials and requires additional analysis [44].…”

Section: Dc-conductivitymentioning

confidence: 99%

The Undoped Polycrystalline Diamond Film—Electrical Transport Properties

Łoś

Fabisiak

Paprocki

et al. 2021

Sensors

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The polycrystalline diamonds were synthesized on n-type single crystalline Si wafer by Hot Filament CVD method. The structural properties of the obtained diamond films were checked by X-ray diffraction and Raman spectroscopy. The conductivity of n-Si/p-diamond, sandwiched between two electrodes, was measured in the temperature range of 90–300 K in a closed cycle cryostat under vacuum. In the temperature range of (200–300 K), the experimental data of the conductivity were used to obtain the activation energies Ea which comes out to be in the range of 60–228 meV. In the low temperature region i.e., below 200 K, the conductivity increases very slowly with temperature, which indicates that the conduction occurs via Mott variable range hopping in the localized states near Fermi level. The densities of localized states in diamond films were calculated using Mott’s model and were found to be in the range of 9×1013 to 5×1014eV−1cm−3 depending on the diamond’s surface hydrogenation level. The Mott’s model allowed estimating primal parameters like average hopping range and hopping energy. It has been shown that the surface hydrogenation may play a crucial role in tuning transport properties.

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“…However, conclusions extracted from resistivity or conductivity are equally applicable. Semiconductors or any other insulating material have a natural temperature dependence of resistivity and can be written as [67]: where ρ DC (T) is DC resistivity, ρ o is a pre-exponential factor, T o is the characteristic temperature, and γ is the exponent whose value can be 1/2 and 1/4 and allows the profile of the density of states (DOS) to be determined. γ = 0.25 corresponds to Mott variable range hopping (VRH) in which hopping probability is optimized, and the defect DOS near the Fermi energy level is slowly varying [68].…”

Section: Electrical Transport Propertiesmentioning

confidence: 99%

Low-frequency electrical response related to oxygen vacancies in Al³⁺ substituted M-type hexaferrite

Singh

Mohapatra

Dobbidi

et al. 2023

J. Phys. D: Appl. Phys.

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The presence of oxygen vacancies is unavoidable in many metal complex oxide materials such as hexaferrite. So, this article investigates the role of crystal defects such as oxygen vacancies, and different oxidation states of Fe ions on electrical conduction behaviours of Al3+ substituted Ba0.4La0.1Sr0.5AlxFe12-xO19 hexaferrite by analyzing temperature dependents AC impedance, and AC conductivity. The optimal substitution of La3+ ions and high-temperature sintering is responsible for forming oxygen vacancies while reducing Fe into Fe3+ to Fe2+ cations, observed in structural and XPS analysis, which affects electrical conduction behaviours. The departure from ideal Debye-type relaxation behavior is also one of the effects of crystal defects. Temperature variation relaxation time observed a sharps change at around 403K. This may be due to different electrical entities influence the mode of electron hopping with the temperature. The activation energy calculated from the temperature dependents relaxation time confirmed the presence of the electron hopping through bridging effects of the first ionization of oxygen vacancies Fe2+-V^.o- Fe3+ below temperature 403K. Whereas, above 403K, electron hopping through different oxidation states of Fe2+ + e → Fe3+ and migration of oxygen vacancies toward the bulk surface are responsible for the conduction mechanism. The DC resistivity and AC conductivity briefs that the bridging effects of oxygen defects can also induce Coulombic interaction between the defects sites resulting in Efros-Shklovskii-Variable-Ranges hopping (ES-VRH) and Correlation-Barrier hopping (CBH) below temperature 403K. Above 403K, polaron-assisted electron hopping is more desirable, as confirmed by Non-Overlapping Small Polaron Tunnelling (NSPT)model.

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Variable range hopping conduction in n-CdSe samples at very low temperature

Cited by 10 publications

References 16 publications

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

The Undoped Polycrystalline Diamond Film—Electrical Transport Properties

Low-frequency electrical response related to oxygen vacancies in Al³⁺ substituted M-type hexaferrite

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Variable range hopping conduction in n-CdSe samples at very low temperature

Cited by 10 publications

References 16 publications

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

The Undoped Polycrystalline Diamond Film—Electrical Transport Properties

Low-frequency electrical response related to oxygen vacancies in Al3+ substituted M-type hexaferrite

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Product

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Low-frequency electrical response related to oxygen vacancies in Al³⁺ substituted M-type hexaferrite