Electrical conduction in CaF2 and CaF2‐Al2O3 nanocomposite films on Al2O3 substrates
Electrical conduction in CaF2 and CaF2‐Al2O3 nanocomposite films on Al2O3 substrates
复制标题
Al2O3 基底上的 CaF2 和 CaF2-Al2O3 纳米复合薄膜的导电性
DOI：
10.1063/1.354657
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发表时间：
1993
影响因子：
3.2
通讯作者：
J. Bates
中科院分区：
文献类型：
--
作者：
F. Modine;D. Lubben;J. Bates
在Al2O3衬底上蒸发了纯CaF2薄膜和Al2O3与CaF2的纳米复合混合物。在一些衬底上的指间电极允许在薄膜生长期间和之后对薄膜中的导电性进行原位测量。研究了电导率与薄膜厚度、沉积速率、成分、时间和温度的关系。在200°C时，靠近Al2O3界面的纯CaF2的电导率有时超过大块CaF2的电导率（即超过50 nm距离的值）多达6700倍。高电导率的特征是活化能为0.6±0.1 eV，明显低于体中导电的活化能约1.0 eV。然而，这种高导电性是热不稳定的，并随着时间的推移而减少。在含有约10 mol % Al2O3作为分散第二相的CaF2薄膜中获得了高但稳定的电导率。在200℃时，两相薄膜的倍率为360 enh。
Thin films of pure CaF2 and nanocomposite mixtures of Al2O3 with CaF2 were evaporated on Al2O3 substrates. Interdigital electrodes on some of the substrates allowed in situ measurements of the electrical conduction in the films during and subsequent to film growth. Electrical conduction was studied as a function of film thickness, film deposition rate, composition, time, and temperature. The electrical conductivity in pure CaF2 adjacent to an Al2O3 interface sometimes exceeded the bulk CaF2 conductivity (i.e., value at more than 50 nm distance) by as much as a factor of 6700 at 200 °C. The high conductivity is characterized by an activation energy of 0.6±0.1 eV, which is significantly lower than the activation energy of about 1.0 eV for conduction in the bulk. However, this high conductivity is thermally unstable and diminishes in time. A high but stable conductivity was obtained in CaF2 films containing about 10 mol % Al2O3 as a dispersed second phase. At 200 °C, a two‐phase film gave a factor of 360 enh...