Kinetic stabilization of Fe film on (4 by 2)-GaAs(100)

TL;DR

This study demonstrates that low-temperature growth of Fe on (4 by 2)-GaAs(100) effectively suppresses As segregation and alloy formation, resulting in a stable, pristine Fe film with minimal interface alloy, even after warming to room temperature.

Contribution

It introduces a low-temperature growth method that stabilizes Fe films on GaAs(100) by reducing interface alloying and segregation, enhancing film quality.

Findings

Suppression of As segregation during low-temperature growth.

Formation of a very thin interface alloy (~8 Å).

Fe film remains stable after warming to room temperature.

Abstract

We grow Fe film on (4 by 2)-GaAs(100) at low temperature, (~ 130 K) and study their chemical structure by photoelectron spectroscopy using synchrotron radiation. We observe the effective suppression of As segregation and remarkable reduction of alloy formation near the interface between Fe and substrate. Hence, this should be a way to grow virtually pristine Fe film on GaAs(100). Further, the Fe film is found stable against As segregation even after warmed up to room temperature. There only forms very thin, ~ 8 angstrom thick interface alloy. It is speculated that the interface alloy forms via surface diffusion mediated by interface defects formed during the low temperature growth of the Fe film. Further out-diffusion of both Ga and As are suppressed because it should then proceed via inefficient bulk diffusion.