1992 Fiscal Year Final Research Report Summary
Preparation of transparent ZnO ceramic with Crystal-Axis Orientation and Development of Functional Materials Combining Piezo electric and Semiconducting Propertes
| Project/Area Number |
03650633
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学・無機材料工学
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| Research Institution | Shonan Institute Technology |
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Principal Investigator |
FUJITSU Satoru SITec, Fac of Engineering, Assoc.Prof., 工学部, 助教授 (20165400)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Zinc Oxide / Transparent Ceramic / Piezoelectric Material / Potential Barrier / Crystal-axis Orientation / Semiconducting Property |
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| Research Abstract |
The technique to obtain the large sample(7mm cube) of transparent ZnO crystal with high crystal-axis orientation has been established. That was attained by using a crystal oriented ZnO as a substrate and its rotation. The Li_2O doping was examined to prepare the Piezo electric material. The only method for Li_2O was the diffusion at high temperature. The small amount of LiCO_3 was painted on the surface of the sample and heated at 800-900ﾟC. The recicling this method was effective to obtain the homogeneous insulator. The electrical-mechanical coupling constant depended on the degree of axis orientation strongly and inhomogenity slightly. The high crystal axis oriented sample without the X-ray diffraction peak from other than (001) and with high resistivity to be 100MOMEGA cm showed high electrical-mechanical coupling constant same as the reported value of single crystal. The light excited current depended on the bias voltage and its applied direction.
The grain boundary model was prepared by appling this method. The prepared ZnO by this method has a c-axis preferencial orientation along to the growth direction. The sample with clear boundary was prepared by using 2 step growth method with the A or C plane as the substrate. It is clear that oxygen plays an important role to develop the potential barrier along the ZnO grain boundary. This prepared sample was used to discuss the effect of lattice matching on such a barrier. The potential barrier was observed in the sample with C-C junction at 90K. The sample with C-A junction which has lattice mismatching did not show the potential barrier. This result suggest that we should discuss the potential barrier with considerration for not only the excess oxygen but also the Piezo effect.
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