Resistive switching characteristics of isolated core-shell iron oxide/germanium nanocrystals epitaxially grown on Si substrates

The core-shell nanostructure of epitaxial Fe3O4 nanocrystals over Ge nuclei showed a large Off/On resistance ratio (similar to 100), which was the largest value in Fe3O4 materials. The nanocrystals with an average diameter of similar to 20 nm were grown epitaxially on Si substrates, whose areal density was high (similar to 10(11) cm(-2)), and each nanocrystal was isolated from each other. The electrical measurement of the individual isolated nanocrystals by conductive-atomic force microscopy showed the bipolartype resistive switching in local voltage-current curves, depending on the Fe-O composition. It was also revealed that activation sites for resistive switching were the Fe3O4/Ge interfaces, where electric-field-induced compositional variation caused large resistive changes. This demonstrated the possibility of developing resistance random access memory devices based on ubiquitous materials. Published by AIP Publishing.