TY - JOUR
T1 - The local structure in heavily boron-doped diamond and the effect this has on its electrochemical properties
AU - Watanabe, Takeshi
AU - Yoshioka, Satoru
AU - Yamamoto, Tomokazu
AU - Sepehri-Amin, Hossein
AU - Ohkubo, Tadakatsu
AU - Matsumura, Syo
AU - Einaga, Yasuaki
N1 - Funding Information:
This study was partly performed as a subject (A-14-KU-0093) on the Advanced Characterization Nanotechnology Platform Japan, and was supported by the JST-CREST Basic Research Program “Creation of Innovative Functions of Intelligent Materials on the Basis of Element Strategy (Research Supervisor: Prof. Kohei Tamao)”. Furthermore, the authors thank Dr. Kazuhiro Hono, National Institute for Materials Science, Tsukuba, for helpful discussions.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/10
Y1 - 2018/10
N2 - Transmission electron microscopy (TEM) coupled with electron energy loss spectroscopy (EELS), and first principles calculations of EEL spectra were utilized to elucidate the relationship between the microscopic structure and the electrochemical properties of heavily boron-doped diamond (h-BDD). The electrochemical properties of h-BDD containing 1 at.% and 3 at.% boron are very different. TEM observations showed that 1 at.% h-BDD consists of small densely packed diamond crystallites, while 3 at.% h-BDD contains small voids and a graphite phase partly along the grain boundaries. The EEL spectrum of the grain interior in 1 at.% h-BDD and comparison of this with a theoretical spectrum shows that the boron atoms are mostly dispersed as single isolated substitutional atoms on diamond lattice sites in the grain interior and that only a small amount of sp2-bonded carbon is present. In contrast, in the grain interior of 3 at.% h-BDD, the boron atoms are mostly associated with nearest neighbor boron pairs, and consequently sp2-bonded carbon is formed. Thus, the local structure has a significant effect on the amount of sp2-bonded carbon. The quite different electrochemical properties of the samples are ascribed to the amount of sp2-bonding arising from the different local structures.
AB - Transmission electron microscopy (TEM) coupled with electron energy loss spectroscopy (EELS), and first principles calculations of EEL spectra were utilized to elucidate the relationship between the microscopic structure and the electrochemical properties of heavily boron-doped diamond (h-BDD). The electrochemical properties of h-BDD containing 1 at.% and 3 at.% boron are very different. TEM observations showed that 1 at.% h-BDD consists of small densely packed diamond crystallites, while 3 at.% h-BDD contains small voids and a graphite phase partly along the grain boundaries. The EEL spectrum of the grain interior in 1 at.% h-BDD and comparison of this with a theoretical spectrum shows that the boron atoms are mostly dispersed as single isolated substitutional atoms on diamond lattice sites in the grain interior and that only a small amount of sp2-bonded carbon is present. In contrast, in the grain interior of 3 at.% h-BDD, the boron atoms are mostly associated with nearest neighbor boron pairs, and consequently sp2-bonded carbon is formed. Thus, the local structure has a significant effect on the amount of sp2-bonded carbon. The quite different electrochemical properties of the samples are ascribed to the amount of sp2-bonding arising from the different local structures.
KW - Boron-doped diamond
KW - Electrochemical properties
KW - Electron energy loss spectroscopy
KW - Local structure
KW - Transmission electron microscopy
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U2 - 10.1016/j.carbon.2018.05.026
DO - 10.1016/j.carbon.2018.05.026
M3 - Article
AN - SCOPUS:85049339070
SN - 0008-6223
VL - 137
SP - 333
EP - 342
JO - Carbon
JF - Carbon
ER -