Structure and electrical properties of indium-germanium interfaces

The structure and electrical properties of ultrathin (a few 10) In films on amorphous germanium are investigated. These films were fabricated by simple vacuum evaporation, without the need for ultrahigh-vacuum or epitaxy techniques. This is made possible by the novel discovery of monolayer growing of In when evaporated on amorphous germanium. This monolayer forms and becomes electrically continuous at a very low average thickness (15), due to good wetting. The growth occurs at room temperature, and is accompanied by crystallization of the Ge underlayer. After the first monolayer is formed, In growth continues by the formation of grains. The samples show interesting two-dimensional electrical properties, including percolation, electron localization, and superconductivity.