Diffusion of oxygen in amorphous Al2O3, Ta2O5, and Nb2O5

作者：Nakamura R^*; Toda T; Tsukui S; Tane M; Ishimaru M; Suzuki T; Nakajima H

来源：Journal of Applied Physics, 2014, 116(3): 033504.

DOI：10.1063/1.4889800

The self-diffusivity of oxygen in amorphous Al2O3 (a-Al2O3), a-Ta2O5, and a-Nb2O5 was investigated along with structural analysis in terms of pair distribution PDF). The low activation energy, similar to 1.2 eV, for diffusion in the oxides suggests a single atomic jump of oxygen ions mediated via vacancy-like defects. However, the pre-exponential factor for a-Ta2O5 and a-Nb2O5 with lower bond energy was two orders of magnitude larger than that for a-Al2O3 with higher bond energy. PDF analyses revealed that the short-range configuration in a-Ta2O5 and a-Nb2O5 was more broadly distributed than that in a-Al2O3. Due to the larger variety of atomic configurations of a-Ta2O5 and a-Nb2O5, these oxides have a higher activation entropy for diffusion than a-Al2O3. The entropy term for diffusion associated with short-range structures was shown to be a dominant factor for diffusion in amorphous oxides.

• 出版日期2014-7-21