We investigate the molecular epitaxy growth mechanisms of 0.5–1 μ m-thick 1 eV-bandgap GaInAsNSb layers lattice-matched to GaAs. A combination of in situ growth monitoring and ex situ measurement techniques was used to optimize the growth conditions in order to achieve the best structural and optoelectronic properties. We demonstrate that, while catastrophic growth breakdown occurs at elevated indium concentrations and growth temperatures, this effect can be effectively suppressed by the surfactant effect of antimony. We show that an informed choice of the substrate temperature during growth can lead to an increased photoluminescence intensity of thick 1 eV GaInAsNSb epilayers by more than one order of magnitude. This work provides new insight into the growth mechanisms of dilute nitride-antimonide alloys and offers practical guidelines for improving the material quality required for high-performance ∼ 1-eV absorbers in next-generation multi-junction solar cells.
Fées et al. (Sun,) studied this question.