Ni-mediated reactions in nanocrystalline diamond on Si substrates: the role of the oxide barrier
| Autor: | Viera Skakalova, Gerlinde Habler, Mária Čaplovičová, Bohuslav Rezek, Semir Tulić, Thomas Waitz, Alexander Kromka, Oleksandr Romanyuk, Marian Varga, Mário Kotlár, Viliam Vretenár |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science General Chemical Engineering Oxide Nanoparticle Heterojunction 02 engineering and technology General Chemistry Chemical vapor deposition 021001 nanoscience & nanotechnology 01 natural sciences Amorphous solid chemistry.chemical_compound Chemical engineering chemistry Nanocrystal Electrical resistivity and conductivity Transmission electron microscopy 0103 physical sciences 0210 nano-technology |
| Zdroj: | RSC Advances. 10:8224-8232 |
| ISSN: | 2046-2069 |
| DOI: | 10.1039/d0ra00809e |
| Popis: | Nanocrystalline diamond (NCD) films grown on Si substrates by microwave plasma enhanced chemical vapor deposition (MWPECVD) were subjected to Ni-mediated graphitization to cover them with a conductive layer. Results of transmission electron microscopy including electron energy-loss spectroscopy of cross-sectional samples demonstrate that the oxide layer on Si substrates (∼5 nm native SiO2) has been damaged by microwave plasma during the early stage of NCD growth. During the heat treatment for graphitizing the NCD layer, the permeability or absence of the oxide barrier allow Ni nanoparticles to diffuse into the Si substrate and cause additional solid-state reactions producing pyramidal crystals of NiSi2 and SiC nanocrystals. The latter are found impinged into the NiSi2 pyramids but only when the interfacial oxide layer is absent, replaced by amorphous SiC. The complex phase morphology of the samples is also reflected in the temperature dependence of electrical conductivity, where multiple pathways of the electronic transport dominate in different temperature regions. We present models explaining the observed cascade of solid-state reactions and resulting electronic transport properties of such heterostructures. |
| Databáze: | OpenAIRE |
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