Low-Energy Electron-Diffraction Study of the Surface Reactions of Germanium with Oxygen and with Iodine. II

The effects of pressure and temperature on the O–Ge and I–Ge surface reaction systems were studied by means of low-energy electron-diffraction with single-crystal (100) and (111) surfaces. The results are very similar to those reported for silicon, but have a displacement to lower temperatures of about 350°C. On both surfaces the oxide films are amorphous, but well-crystallized two-dimensional iodide structures were obtained and the transitions to the iodides are ``reconstructive.'' The slopes for all four transitions from the ``clean'' surfaces correspond to energies of about 55 kcal/mole. Clustering phenomena are also discussed.