DC electrical properties of amorphous carbon with different bonding hybridization

Moustafa, S.H.; Koós, M.; Pócsik, I.

doi:10.1016/s0022-3093(98)00253-1

Cited by 24 publications

(10 citation statements)

References 17 publications

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“…Previous studies on amorphous carbons and carbon nitrides revealed that these covalent glasses followed the BTH mechanism, rather than the VRH mechanism. [20][21][22] The results listed in Table I also reveal that the energy differences between the mobility edge (E C ) and the Fermi level (E F ) decrease with increasing pyrolysis temperature. One explanation for such variation is that the E F is moving closer to E C with increasing pyrolysis temperature.…”

Section: Resultsmentioning

confidence: 86%

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Electron Transport in Polymer‐Derived Amorphous Silicon Oxycarbonitride Ceramics

Wang

Jiang

Zhang

et al. 2009

Journal of the American Ceramic Society

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The electron transport behavior of polymer‐derived amorphous silicon oxycarbonitride ceramics is studied by measuring their temperature‐dependent electrical conductivities. The experimental results are analyzed using theoretical models. The results reveal that the materials exhibit three conduction mechanisms: conduction in extended states, conduction in band tails, and conduction in localized states. Particularly, it is found that in a low‐temperature regime, the conduction of the materials follows a band tail hopping mechanism, rather than the previously assumed variable range hopping mechanism. The results also reveal that energy gaps such as EC−EF and EC−EA decrease with increasing pyrolysis temperature.

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Section: Resultsmentioning

confidence: 86%

“…A very good linear fit suggests that the SiOCNs studied here follow the BTH conduction mechanism, rather than the previously assumed VRH mechanism. Previous studies on amorphous carbons and carbon nitrides revealed that these covalent glasses followed the BTH mechanism, rather than the VRH mechanism 20–22 …”

Section: Resultsmentioning

confidence: 99%

Electron Transport in Polymer‐Derived Amorphous Silicon Oxycarbonitride Ceramics

Wang

Jiang

Zhang

et al. 2009

Journal of the American Ceramic Society

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“…Godet [7] showed that for a given range value of localization parameter (LP) (10 À5 -1) and if monophonic VRH is the predominant transport mechanism, for an exponential DOS energy dependence, a linear correspondence between lnðr 00 Þ and T 1=4 0 must exist. However, as Moustafa et al [11] have pointed out, the apparent linear temperature dependence of lnðr 00 Þ and T 1=4 0 does not relate to conduction by VRH of carriers in the band of localized states near de Fermi level.…”

Section: Introductionmentioning

confidence: 94%

Hopping mechanism of electric transport in intrinsic and p-doped nanocrystalline silicon thin films

Concari

Buitrago‐Sierra

2004

Journal of Non-Crystalline Solids

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“…However, many authors have found that quantitative estimates for the localization radius (deduced from s 00 and T 0 ) and for N(E F ) (deduced from T 0 ) were difficult to reconcile with other physical parameters in amorphous films such as a-Si, a-Ge and a-C [19,23,[43][44][45][46][47].…”

Section: Density Of States At the Fermi Levelmentioning

confidence: 99%

Electronic Localization and Bandtail Hopping Charge Transport

Godet

2002

phys. stat. sol. (b)

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Our previous modeling of hopping in localized bandtails has improved the description of electrical transport in amorphous carbon films and elemental amorphous semiconductors. This model is further developed to understand the role of the wavefunction localization radius g --1 and density of states (DOS) distribution N(E) on the T dependence of the conductivity and the thermopower in disordered solids. Using values of the localization parameter LP ¼ N(E F ) g --3 in the range from 10 --4 to 1 eV --1 , our simulations show that: (i) The assumption of extremely low LP values made in previous works is often irrelevant for comparison with experiments. (ii) For low temperatures or large LP values, a linear relation holds between the dominant transport energy (E t --E F ) and temperature (with a stronger dependence as LP decreases) while a logarithmic dependence is obtained in the high-T range for small LP values. (iii) In the weak localization condition, a T-independent thermopower S(T) is predicted with an absolute value of eS/k % (LP) --1/3 . (iv) The relationship sT 1/2 ¼ s 00 exp (--(T 0 /T ) 1/4 ) holds, as expected for 3D hopping, over a wide temperature range (50-500 K); using the LP value as a parameter, the positive linear correlation between ln (s 00 ) and T 1=4 0 is a signature of an exponential localized bandtail distribution, clearly incompatible with Mott's hypothesis for 'Variable Range Hopping' in an energy-independent DOS distribution near the Fermi level.

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DC electrical properties of amorphous carbon with different bonding hybridization

Cited by 24 publications

References 17 publications

Electron Transport in Polymer‐Derived Amorphous Silicon Oxycarbonitride Ceramics

Electron Transport in Polymer‐Derived Amorphous Silicon Oxycarbonitride Ceramics

Hopping mechanism of electric transport in intrinsic and p-doped nanocrystalline silicon thin films

Electronic Localization and Bandtail Hopping Charge Transport

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