| A Surface Etching for Synthetic Diamonds with Nano-Thick Ni Films and Low Temperature Annealing |
| Jeongho Song, Yunyoung Noh, Ohsung Song |
| Department of Materials Science and Engineering, University of Seoul |
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| ABSTRACT |
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Ni (100 nm thick) was deposited onto synthesized diamonds to fabricate etched diamonds. Next, those diamonds were annealed at varying temperatures ($400{sim}1200^{circ}C$) for 30 minutes and then immersed in 30 wt% $HNO_3$ to remove the Ni layers. The etched properties of the diamonds were examined with FE-SEM, micro-Raman, and VSM. The FE-SEM results showed that the Ni agglomerated at a low annealing temperature (${sim}400^{circ}C$), and self-aligned hemisphere dots formed at an annealing temperature of $800^{circ}C$. Those dots became smaller with a bimodal distribution as the annealing temperature increased. After stripping the Ni layers, etch pits and trigons formed with annealing temperatures above $400^{circ}C$ on the surface of the diamonds. However, surface graphite layers existed above $1000^{circ}C$. The B-H loop results showed that the coercivity of the samples increased to 320 Oe (from 37 Oe) when the annealing temperature increased to $600^{circ}C$ and then, decreased to 150 Oe with elevated annealing temperatures. This result indicates that the coercivity was affected by magnetic domain pinning at temperatures below $600^{circ}C$ and single domain behavior at elevated temperatures above $800^{circ}C$ consistent with the microstructure results. Thus, the results of this study show that the surface of diamonds can be etched. |
| Key words:
Synthetic diamond, Diamond etching, Nickel thin film, Vibrating sample magnetometer, Low temperature annealing |
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