Control of defect-mediated tunneling barrier heights in ultrathin MgO films

• Published in: Applied physics letters Vol. 97; no. 26; pp. 263502 - 263502-3
• Main Authors: Kim, D. J., Choi, W. S., Schleicher, F., Shin, R. H., Boukari, S., Davesne, V., Kieber, C., Arabski, J., Schmerber, G., Beaurepaire, E., Jo, W., Bowen, M.
• Format: Journal Article
• Language: English
• Published: American Institute of Physics 27-12-2010
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.3531652

The impact of oxygen vacancies on local tunneling properties across rf-sputtered MgO thin films was investigated by optical absorption spectroscopy and conducting atomic force microscopy. Adding
O
2
to the Ar plasma during MgO growth alters the oxygen defect populations, leading to improved local tunneling characteristics such as a lower density of current hotspots and a lower tunnel current amplitude. We discuss a defect-based potential landscape across ultrathin MgO barriers.