Reflection high‐energy electron diffraction intensity oscillations and anisotropy on vicinal AlAs(001) during molecular‐beam epitaxy

We have examined the reflection high‐energy electron diffraction (RHEED) specular beam intensity oscillations on vicinal AlAs(001) which was grown on GaAs(001) substrates misoriented by 2° or 3° toward [110], [010], and [110]. The temperature dependence of the RHEED oscillation behavior on vicinal surfaces is similar to that on GaAs(001) and InAs(001). The cation flux and misorientation angle dependencies of Tc on AlAs(001) also followed the same pattern as on GaAs(001), as expected. Similarly, the same anisotropic behavior was also obtained, in that Tc[110]≳Tc[110]. Unlike GaAs(001), however, the surface reconstruction could not be kept constant during the growth mode transition and it is therefore very difficult to analyze AlAs(001) data in as much detail as that for GaAs(001), but from the similarity between them we have qualitatively estimated the effective surface migration barrier for Al adatoms on AlAs(001) as ∼1.74 eV.