Abstract
The observation of diffuse scattering due to short-range order ( SRO) between Al and Ga atoms in (Al_0.5 Ga_0.5)As which were grown by molecular beam epitaxy, has been made using both electron and X-ray diffraction methods. Only diffuse streaks along the <110> direction were detected, the origin of which must be low frequency transverse acoustic phonons. The absence of SRO diffuse scattering is considered as an evidence of random distribution of Al and Ga atoms in this substance, consistent with the thermodynamical calculation by Onabe ( K. Onabe: Jpn. J. Appl. Phys. 21 (1982) L323).
