Adatom kinetics on and below the surface: the existence of a new diffusion channel

Phys Rev Lett. 2003 Feb 7;90(5):056101. doi: 10.1103/PhysRevLett.90.056101. Epub 2003 Feb 6.


Employing density-functional theory in combination with scanning tunneling microscopy, we demonstrate that a thin metallic film on a semiconductor surface may open an efficient and hitherto not expected diffusion channel for lateral adatom transport: adatoms may prefer diffusion within this metallic layer rather than on top of the surface. Based on this concept, we interpret recent experiments: We explain why and when In acts as a surfactant on GaN surfaces, why Ga acts as an autosurfactant, and how this mechanism can be used to optimize group-III nitride growth.