The induction of a graphite-like phase by Fe-coating/post-annealing process to improve the electron field emission properties of ultrananocrystalline diamond films
| Autor: | Wen-Ching Shih, Kuang-Yau Teng, I.-Nan Lin, Pin-Chang Huang |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Materials science
Mechanical Engineering Diamond Nanotechnology General Chemistry Carbon nanotube engineering.material Electronic Optical and Magnetic Materials law.invention Nanoclusters Crystallinity Field electron emission Coating Chemical engineering law Phase (matter) Materials Chemistry engineering Graphite Electrical and Electronic Engineering |
| Zdroj: | Diamond and Related Materials. 24:188-194 |
| ISSN: | 0925-9635 |
| Popis: | The electron field emission (EFE) process for ultrananocrystalline diamond (UNCD) films was tremendously enhanced by Fe-coating and post-annealing processes. The extent of enhancement changes with the granular structure of the UNCD films and the post-annealing conditions (temperature and atmosphere). The best EFE properties are obtained by post-annealing the films at 900 °C in an H 2 environment for 5 min. The EFE behavior of the films can be turned on at E 0 = 1.28 V/μm, attaining a large EFE current density of 772 μA/cm 2 at an applied field of 8.8 V/μm. Microstructural analysis indicates that the mechanism for the improvement in the EFE process is the formation of graphene-like phase (a-few-layer graphite) with good crystallinity, surrounding the Fe (or Fe 3 C) nanoclusters. Presumably, the nanographites were formed via the reaction of Fe-clusters with diamond films, viz. the Fe-clusters dissolved the carbons in the diamond grains and the re-precipitated them on the surface of the other side of clusters, a process similar to the growth of carbon nanotubes via Fe clusters as catalyst. |
| Databáze: | OpenAIRE |
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