Low Schottky barriers on n-type silicon (001)

It has been reported that no metal shows a Schottky barrier of less than 0.4 eV on n-type silicon (001). This is attributed to interface states between metal and silicon (001), which pin the interface Fermi level and make the Schottky barrier more or less independent of the metal work function. We demonstrate that, by terminating dangling bonds and relaxing strained bonds on the silicon (001) surface with a monolayer of selenium, low Schottky barriers can be obtained on n-type silicon (001). Aluminum and chromium show barrier heights of 0.08 and 0.26 eV on n-type silicon (001), respectively. These results agree well with the ideal Schottky barrier heights for aluminum and chromium on n-type silicon (001), but are significantly different from the experimental barrier heights known for four decades for these metals on n-type silicon (001).