Investigate the effects of sample preparation processes on the electronic structure of resistive switching materials

Jau-Wern Chiou^1,2*, Joan-Yi Wang¹, Zhen-Gang Jiang¹, Yu-Ting Hu¹, Zheng-Da Li¹, Y. M. Hu¹, Wen-Hui Cheng³, Jen-Sue Chen³

¹Department of Applied Physics, National University of Kaohsiung, Kaohsiung, Taiwan
²Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
³Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan

* Presenter:Jau-Wern Chiou, email:jwchiou@nuk.edu.tw

Transition metal oxide thin films have been studied widely due to it possessed various physical properties including ferromagnetism, semiconducting property, photoelectric effect, resistive switching behaviors. Especially, as a p-type semiconductor, some applications of its components show the unique optical, electrical, and magnetic properties.
We have successfully prepared CuOx thin films on sapphire and silicon substrates using magnetron sputtering method under different annealing temperatures and gas ambiances. The XRD results present that the crystallinity of CuOx thin films tends to CuO and Cu2O structure as prepared on O2 and N2 ambiances, respectively, regardless of substrates. In addition, the preferential orientation of CuOx thin films strongly depends on the annealing temperature. Moreover, this study investigates the electronic and atomic structures of the CuO and Cu2O thin films. Our experimental techniques include x-ray absorption near-edge structure (XANES), extended x-ray absorption fine structure (EXAFS), x-ray photoelectron spectroscopy (XPS), and resonant inelastic x-ray scattering (RIXS) using synchrotron radiation sources at National Synchrotron Radiation Research Center (NSRRC, Taiwan). We propose to obtain a fundamental understanding of the scientific principles that predominates the chemical bonding, electronic and atomic structures of resistive switching materials.

Keywords: resistive switching materials, XANES, EXAFS, XPS, RIXS