Charge transport through localized states in sputtered amorphous silicon suboxides

Hapert, J.J. van; Tomozeiu, N.; Faassen, Ernst E. van; Vredenberg, A. M.; Habraken, F.H.P.M.

doi:10.1557/proc-666-f3.6

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…In regime I ( Figure 8 ), conduction is considered to occur within the amorphous silica network, as the amount of sp 2 carbon is very low (ϕ C < 1 vol.%) [ 70 , 71 ]. According to Hapert, high concentration of silicon dangling bonds is present within amorphous silica SiO x , showing a VRH transport within localized states [ 70 , 71 ]. A VRH conduction mechanism is also likely for low-carbon SiOC/C materials.…”

Section: Resultsmentioning

confidence: 99%

Effect of the Content and Ordering of the sp2 Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides

et al. 2020

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The present work elaborates on the correlation between the amount and ordering of the free carbon phase in silicon oxycarbides and their charge carrier transport behavior. Thus, silicon oxycarbides possessing free carbon contents from 0 to ca. 58 vol.% (SiOC/C) were synthesized and exposed to temperatures from 1100 to 1800 °C. The prepared samples were extensively analyzed concerning the thermal evolution of the sp2 carbon phase by means of Raman spectroscopy. Additionally, electrical conductivity and Hall measurements were performed and correlated with the structural information obtained from the Raman spectroscopic investigation. It is shown that the percolation threshold in SiOC/C samples depends on the temperature of their thermal treatment, varying from ca. 20 vol.% in the samples prepared at 1100 °C to ca. 6 vol.% for the samples annealed at 1600 °C. Moreover, three different conduction regimes are identified in SiOC/C, depending on its sp2 carbon content: (i) at low carbon contents (i.e., <1 vol.%), the silicon oxycarbide glassy matrix dominates the charge carrier transport, which exhibits an activation energy of ca. 1 eV and occurs within localized states, presumably dangling bonds; (ii) near the percolation threshold, tunneling or hopping of charge carriers between spatially separated sp2 carbon precipitates appear to be responsible for the electrical conductivity; (iii) whereas above the percolation threshold, the charge carrier transport is only weakly activated (Ea = 0.03 eV) and is realized through the (continuous) carbon phase. Hall measurements on SiOC/C samples above the percolation threshold indicate p-type carriers mainly contributing to conduction. Their density is shown to vary with the sp2 carbon content in the range from 1014 to 1019 cm−3; whereas their mobility (ca. 3 cm2/V) seems to not depend on the sp2 carbon content.

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Section: Resultsmentioning

confidence: 99%

Effect of the Content and Ordering of the sp2 Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides

et al. 2020

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“…5). The temperature dependence of resistance seems to follow the model for variable-range hopping (VRH) in 3-dimensions272829303132, however, the calculated localization length and density of electronic states give unrealistic values (see Supplementary Information). Instead, multiphonon hopping (MPH) is assumed to be governing the charge transfer mechanism33.…”

Section: Resultsmentioning

confidence: 99%

Industrially benign super-compressible piezoresistive carbon foams with predefined wetting properties: from environmental to electrical applications

Pham

Samikannu

Kukkola

et al. 2014

Sci Rep

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In the present work electrically conductive, flexible, lightweight carbon sponge materials derived from open-pore structure melamine foams are studied and explored. Hydrophobic and hydrophilic surface properties - depending on the chosen treatment conditions - allow the separation and storage of liquid chemical compounds. Activation of the carbonaceous structures substantially increases the specific surface area from ~4 m2g−1 to ~345 m2g−1, while retaining the original three-dimensional, open-pore structure suitable for hosting, for example, Ni catalyst nanoparticles. In turn the structure is rendered suitable for hydrogenating acetone to 2-propanol and methyl isobutyl ketone as well for growing hierarchical carbon nanotube structures used as electric double-layer capacitor electrodes with specific capacitance of ~40 F/g. Mechanical stress-strain analysis indicates the materials are super-compressible (>70% volume reduction) and viscoelastic with excellent damping behavior (loss of 0.69 ± 0.07), while piezoresistive measurements show very high gauge factors (from ~20 to 50) over a large range of deformations. The cost-effective, robust and scalable synthesis - in conjunction with their fascinating multifunctional utility - makes the demonstrated carbon foams remarkable competitors with other three-dimensional carbon materials typically based on pyrolyzed biopolymers or on covalently bonded graphene and carbon nanotube frameworks.

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Study of the a-Si/a-SiO2 interface deposited by r.f. magnetron sputtering

et al. 2004

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Charge transport through localized states in sputtered amorphous silicon suboxides

Cited by 3 publications

References 11 publications

Effect of the Content and Ordering of the sp2 Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides

Effect of the Content and Ordering of the sp2 Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides

Industrially benign super-compressible piezoresistive carbon foams with predefined wetting properties: from environmental to electrical applications

Study of the a-Si/a-SiO2 interface deposited by r.f. magnetron sputtering

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