Antiphase boundaries in InGaP/SiGe/Si : structural and optical properties

Integration of III-V photonics on Si substrate remains a very hot topic in recent years[1,2]. GaP shows a strong advantage of low-lattice mismatch to Si and has been widely studied. However, the GaP material has an indirect bandgap and relatively low carrier mobility, which intrinsically limit its optical performances. Therefore, the pseudomorphic integration of InGaP on a relaxed SiGe/Si pseudo-substrate is expected to overcome these issues. In this work, the optical properties of an InGaP/SiGe/Si sample were studied by temperature-and power-dependent photoluminescence (PL). With the additional help of transmission electron microscopy images and chemical mechanical polishing technique, one PL emission peak is found to come from surface InP quantum dots. Other PL emission peak with a superlinear power dependence is tentatively considered to be co-contributed by InGaP host material[3] and In-rich antiphase boundaries, in good correlation with theoretical predictions[4].