Elimination of phase separation in metalorganic chemical vapor deposition-grown GaInP epilayers by compositionally step-graded Ga1-x Inx P multilayers

In this paper, we report on the influence of compositionally step-graded Ga1-x Inx P multilayers on the microstructural and optical properties of In-rich Ga0.46 In0.54 P film grown on a GaAs substrate. Based on the transmission electron microscope observation, the growth of Ga0.46 In0.54 P on GaAs was found to result in phase separation, which was due to the strain-induced composition pulling effect. This phase separation could be successfully eliminated by the step-graded Ga1-x Inx P multilayers with optimized thickness. The elimination was caused by the sufficient moderation of compressive strain in the subsequently grown Ga0.46 In0.54 P film. The employment of step-graded Ga1-x Inx P multilayers was also helpful in improving compositional uniformity and photoluminescence property of the subsequently grown film. The compositional dependence of the film structure and the ab initio elastic constants were used to show that Ga1-x Inx P multilayers with a systematic increase in the In-rich compositional regime exhibit epitaxial stability.