X-ray diffraction study on the correlation between ordered domains size and ordering degree in InGaP/GaAs alloy layers

Summary. -Undoped heteroepitaxial layers of InGaP with constant-thickness grown lattice matched on GaAs substrates with miscut angles of 0°, 2°, 6° with respect to the (001) plane and n- and p-doped samples grown on 2° off substrates have been studied by X-ray diffraction. The examined InGaP layers spontaneously order in CuPt-like domains presenting (- 1,1,1) and (1, -1, 1) variants. The doubling of periodicity has been revealed by the appearance of extra reflections normally forbidden. The full width at half maximum and the integrated intensity of these reflections were measured in order to investigate the degree of order within the domains and the results have been discussed on the basis of the con-elation between domains size and ordering degree. Finally, the doping level effects (Si [n] and Zn [p]) on the cationic ordering has been analysed.