科研之友
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摘要
The electron-irradiation-induced crystallization of amorphous Al2O3 (a-Al2O3) was investigated by in-situ transmission electron microscopy under the wide electron-energy region of 25-300 keV. The formation of gamma-Al2O3 nanocrystallites was induced by irradiating the a-Al2O3 thin film along with the formation of nanovoids in the crystalline grains regardless of the acceleration voltage. The crystallization became more pronounced with decreasing the electron energy, indicating that electronic excitation processes play a dominant role in the formation of gamma-Al2O3. Radial distribution analyses suggested that a-Al2O3 transforms to c-phase via the %26quot;excited%26quot; (%26quot;stimulated%26quot;) amorphous state, in which the breaking and rearrangement of unstable short-range Al-O bonds, i.e., fivefold-coordinated Al-O (AlO5) basic units, occur.
- 出版日期2013-2-14
