[11p-Z07-1~14] 6.3 Oxide electronics

[11p-Z07-12] Direct Observation of Electronic Structure of Amorphous Alumina ReRAM by Synchrotron Radiation

〇Seiichi Kato¹, Seisuke Nigo¹, Masato Kubota², Kenta Amemiya³ (1.NIMS, 2.JAEA, 3.KEK IMSS)

Keywords:ReRAM, amorphous alumina, synchrotron radiation

We proposed a model to explain the switching effect of amorphous alumina with a moderate density of oxygen vacancies. When electrons do not exist at oxygen vacancy (Vo), the Vo is regarded as a divalent pseudo atom (Vo⁺²). Vo⁺² becomes Vo⁺¹ by an electron injection When the number of injected electrons exceeds the threshold, Vo⁺¹ electrons overlap and delocalize, and the conductive electronic sub-band is generated. To detect differences in the electronic structure between ON- and OFF- state in an element-selective manner, we performed X-ray absorption spectroscopy measurements with a high energy resolution. When we confirmed the X-ray absorption spectra of the ON- and OFF-samples near the O and Al K-absorption edge, a spectral peak is observed only in the ON-sample near the O K-absorption edge. We conclude that the peak is caused by conductive sub-band newly created in ON-sample.