Rosenburg, Felix ; Balke, Benjamin ; Nicoloso, Norbert ; Riedel, Ralf ; Ionescu, Emanuel (2023)
Effect of the Content and Ordering of the sp² Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides.
In: Molecules, 2020, 25 (24)
doi: 10.26083/tuprints-00017448
Artikel, Zweitveröffentlichung, Verlagsversion
 | Es ist eine neuere Version dieses Eintrags verfügbar. |
Kurzbeschreibung (Abstract)
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.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2023 |
| Autor(en): | Rosenburg, Felix ; Balke, Benjamin ; Nicoloso, Norbert ; Riedel, Ralf ; Ionescu, Emanuel |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Effect of the Content and Ordering of the sp² Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides |
| Sprache: | Englisch |
| Publikationsjahr: | 20 November 2023 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 2020 |
| Ort der Erstveröffentlichung: | Basel |
| Verlag: | MDPI |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Molecules |
| Jahrgang/Volume einer Zeitschrift: | 25 |
| (Heft-)Nummer: | 24 |
| Kollation: | 17 Seiten |
| DOI: | 10.26083/tuprints-00017448 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/17448 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichung DeepGreen |
| Kurzbeschreibung (Abstract): | 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. |
| Freie Schlagworte: | silicon oxycarbides, charge carrier transport, free carbon, Raman spectroscopy, Hall measurements |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-174483 |
| Zusätzliche Informationen: | This article belongs to the Special Issue Molecular-Level Processing and Chemical Properties of Functional Ceramic Materials |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe |
| Hinterlegungsdatum: | 20 Nov 2023 09:58 |
| Letzte Änderung: | 21 Nov 2023 06:25 |
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| Suche nach Titel in: | TUfind oder in Google |
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- Effect of the Content and Ordering of the sp² Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides. (deposited 20 Nov 2023 09:58) [Gegenwärtig angezeigt]
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