InAsSb quantum dots (QDs) grown by metalorganic vapor phase epitaxy on In0.53Ga0.47As/InP under different TMSb/AsH3 flow ratios have been characterized by means of continuous wave and time-resolved photoluminescence (PL) as well as Raman scattering. It was found that the flow ratio has a very strong influence on the QD composition, PL peak energies, and carrier recombination times. While the samples prepared using low TMSb/AsH3 flow ratios show a bimodal character with both InAs and InAsSb QDs present, in the structures grown at high flow ratios the InAsSb QDs dominate, showing strong photoluminescence intensity, fast carrier capture and slow recombination.