Abstract
Group‐III‐ and group‐V‐induced intensity oscillations of reflection high‐energy electron diffraction are observed for InAsP in gas‐source molecular beam epitaxial growth. The As incorporation rate is found to be dominant, independent of the presence of P when the phosphine flow rate is reasonably low. This observation suggests a simple method of controlling the As composition in InAsP by just controlling the incorporation‐rate ratio of As to In when this ratio is less than unity. This successful in situ composition control for InAsP, combined with the in situ composition calibration in GaAsP reported previously, provides a general guideline for controlling the compositions in InGaAsP.