Sakaguchi Norihito, Tanda Luka, Kunisada Yuji
Laboratory of Integrated Function Materials, Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Laboratory of Integrated Function Materials, Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Ultramicroscopy. 2016 Oct;169:37-43. doi: 10.1016/j.ultramic.2016.07.003. Epub 2016 Jul 6.
The dielectric function of α-Al2O3 was measured by electron energy-loss spectroscopy (EELS) coupled with the difference method. The influence of Cerenkov radiation was significant in measurements using a 200kV transmission electron microscope (TEM) and the correct dielectric function could not be obtained using the conventional EELS procedure. However, a good agreement between the optical data and EELS for the dielectric functions was obtained via a 60kV TEM. Combining EELS and the difference method, however, provided an accurate measurement of the dielectric function for α-Al2O3 even at an accelerating voltage of 200kV. The combination of EELS and the difference method in the nano-beam diffraction mode could derive an accurate dielectric function with superior spatial resolution regardless of the occurrence of Cerenkov radiation.
采用电子能量损失谱（EELS）结合差值法测量了α-Al2O3的介电函数。在使用200kV透射电子显微镜（TEM）进行测量时，切伦科夫辐射的影响显著，采用传统的EELS程序无法获得正确的介电函数。然而，通过60kV TEM获得了光学数据与EELS介电函数之间的良好一致性。不过，即使在200kV加速电压下，将EELS与差值法相结合也能准确测量α-Al2O3的介电函数。在纳米束衍射模式下，将EELS与差值法相结合，无论是否发生切伦科夫辐射，都能获得具有卓越空间分辨率的准确介电函数。
