Co/AlOx/Co with AlOxbarriers of various oxidation states were fabricated and investigated using inelastic electron tunneling (IET) spectroscopy and X-ray photoelectron spectroscopy (XPS). XPS revealed that AlOxoxidized for 8 h contained an inhomogeneous distribution of metallic Al, whereas AlOxoxidized for 24 h contained a homogeneous distribution. The inhomogeneous and homogeneous distributions of metallic Al corresponded to asymmetric and symmetric IET spectra, respectively. These junctions showed peaks at ± 0.03 V. AlOxoxidized for 168 h contained no metallic Al, and this junction had no peaks, suggesting that peaks at ± 0.03 V originate from metallic Al. © 2009 Elsevier B.V. All rights reserved.
Horikiri, K., Morizumi, M., & Shiiki, K. (2009). Estimation of oxidation states of AlOx barriers in a tunneling junction by inelastic electron tunneling spectroscopy. Thin Solid Films, 517(18), 5576–5579. https://doi.org/10.1016/j.tsf.2009.03.064