Atomically resolved images of bismuth films on mica with an atomic force microscope

Bi(111) films grown on mica substrates and then exposed to air have been imaged with an atomic force miroscope in 0.01 M HCl. By exposing the Bi(111) to air, layers of Bi oxide are readily formed, which can be removed by imaging in HCl. The images are atomically resolved and show two types of structure: large epitaxial areas of hexagonal structure with a spacing of 7.6 Å, and a few smaller regions with a spacing of 4.5 Å. The former agrees well with the (√3×√3)R30° structure of an overlayer of atomic oxygen atoms adsorbed on Bi(111), and the latter with the uncovered Bi(111) surface.