TY - JOUR
T1 - Atomic and electronic structures of Cu/α-Al2O3 interfaces prepared by pulsed-laser deposition
AU - Sasaki, Takeo
AU - Matsunaga, Katsuyuki
AU - Ohta, Hiromichi
AU - Hosono, Hideo
AU - Yamamoto, Takahisa
AU - Ikuhara, Yuichi
N1 - Funding Information:
The authors wish to thank Drs T. Mizoguchi, S. Tanaka and M. Kohyama for fruitful discussions. This work was performed as a part of Nanostructure Coating Project carried out by New Energy and Industrial Technology Development Organization. This work is also supported in part by a grant for 21st Century COE Program “Human-Friendly Materials Based on Chemistry” from the Ministry of Education, Culture, Sports, Science and Technology of Japan.
PY - 2003/11
Y1 - 2003/11
N2 - Interfacial atomic structures of Cu/Al2O3(0001) and Cu/Al2O3(112̄0) systems prepared by a pulsed-laser deposition technique have been characterized by using high-resolution transmission electron microscopy (HRTEM). It was found that Cu metals were epitaxially oriented to the surface of Al2O3 substrates, and the following orientation relationships (ORs) were found to be formed: (111)Cu//(0001)Al2O3, [11̄0] Cu//[11̄00]Al2O3 in the Cu/Al 2O3(0001) interface and (001) Cu//(112̄0)Al2O3, [11̄0] Cu//[0001]Al2O3 in the Cu/Al2O 3(112̄0) interface. Geometrical coherency of the Cu/Al 2O3 system has been evaluated by the coincidence of reciprocal lattice points method, and the result showed that the most coherent ORs were (111)Cu//(0001)Al2O3, [112̄] Cu//[11̄00]Al2O3 and (11̄0) Cu//(112̄0)Al2O3, [111] Cu//[0001]Al2O3, which are equivalent to each other. These ORs were not consistent with the experimentally observed ORs, and it was possible that crucial factors to determine the ORs between Cu and Al 2O3 were not only geometrical coherency, but also other factors such as chemical bonding states. Therefore, to understand the nature of the interface atomic structures, the electronic structures of the Cu/Al 2O3 interfaces have been investigated by electron energy-loss spectroscopy. It was found that the pre-edge at the lower energy part of the main peak appeared in the O-K edge spectra at the interface region in both the Cu/Al2O3(0001) and Cu/Al2O 3(112̄0) systems. This indicates the existence of Cu-O interactions at the interface. In fact, HRTEM simulation images based on O-terminated interface models agreed well with the experimental images, indicating that O-terminated interfaces were formed in both systems. Since the overlapped Cu atomic density in the experimental ORs were larger than that in the most coherent OR, it is considered that the on-top Cu-O bonds stabilize the O-terminated Cu/Al2O3 interfaces.
AB - Interfacial atomic structures of Cu/Al2O3(0001) and Cu/Al2O3(112̄0) systems prepared by a pulsed-laser deposition technique have been characterized by using high-resolution transmission electron microscopy (HRTEM). It was found that Cu metals were epitaxially oriented to the surface of Al2O3 substrates, and the following orientation relationships (ORs) were found to be formed: (111)Cu//(0001)Al2O3, [11̄0] Cu//[11̄00]Al2O3 in the Cu/Al 2O3(0001) interface and (001) Cu//(112̄0)Al2O3, [11̄0] Cu//[0001]Al2O3 in the Cu/Al2O 3(112̄0) interface. Geometrical coherency of the Cu/Al 2O3 system has been evaluated by the coincidence of reciprocal lattice points method, and the result showed that the most coherent ORs were (111)Cu//(0001)Al2O3, [112̄] Cu//[11̄00]Al2O3 and (11̄0) Cu//(112̄0)Al2O3, [111] Cu//[0001]Al2O3, which are equivalent to each other. These ORs were not consistent with the experimentally observed ORs, and it was possible that crucial factors to determine the ORs between Cu and Al 2O3 were not only geometrical coherency, but also other factors such as chemical bonding states. Therefore, to understand the nature of the interface atomic structures, the electronic structures of the Cu/Al 2O3 interfaces have been investigated by electron energy-loss spectroscopy. It was found that the pre-edge at the lower energy part of the main peak appeared in the O-K edge spectra at the interface region in both the Cu/Al2O3(0001) and Cu/Al2O 3(112̄0) systems. This indicates the existence of Cu-O interactions at the interface. In fact, HRTEM simulation images based on O-terminated interface models agreed well with the experimental images, indicating that O-terminated interfaces were formed in both systems. Since the overlapped Cu atomic density in the experimental ORs were larger than that in the most coherent OR, it is considered that the on-top Cu-O bonds stabilize the O-terminated Cu/Al2O3 interfaces.
KW - Coincidence of reciprocal lattice points method
KW - Cu/AlO
KW - Electron energy-loss spectroscopy
KW - High-resolution transmission electron microscopy
KW - Metal-ceramic interface
KW - Pulsed-laser deposition
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U2 - 10.1016/j.stam.2003.12.003
DO - 10.1016/j.stam.2003.12.003
M3 - Article
AN - SCOPUS:1642359190
VL - 4
SP - 575
EP - 584
JO - Science and Technology of Advanced Materials
JF - Science and Technology of Advanced Materials
SN - 1468-6996
IS - 6
ER -