Kinetic stabilization of a pristine Fe film on (4×2)-GaAs(100)

Abstract

We grow Fe films on (4x2)-GaAs(100) at room temperature and low substrate temperature (similar to 130 K) and study their chemical structure by high-resolution photoelectron spectroscopy using synchrotron radiation. We find direct spectroscopic evidence for the effective suppression of the outdiffusion of both Ga and As from the substrate by the low temperature growth. Further, the Fe film is found to be stable even after warming up to 400 K. The thermal stability of the Fe film has kinetic origin; the diffusion of both Ga and As from the substrate through the already existing Fe film is expected to proceed via bulk diffusion that is much less efficient and thus a rate limiting process.