Characterization of all-chromium tunnel junctions and single-electron tunneling devices fabricated by direct-writing multilayer technique

We report about the fabrication and analysis of the properties of Cr/CrOx/Cr tunnel junctions and single-electron tunneling transistors, prepared by different variants of direct-writing multilayer technique. In all cases, the chromium oxide tunnel barriers were formed in air under ambient conditions. From the experiments on single junctions, values for the effective barrier height and thickness were derived. For the all-chromium single-electron tunneling transistors, we achieved minimal junction areas of 17×60 nm2 using a scanning transmission electron microscope for the e-beam exposure on Si3N4 membrane substrate. We discuss the electrical performance of the transistor samples as well as their noise behavior.