In this paper,we report the growth of Ga As Sb and its crystalline property under various Sb2/As2 flux ratios and growth temperatures.We simulated the incorporation difference between Sb2 and As2 by using a non-equilibrium thermodynamic model.Our study of Ga As Sb growth has successfully yielded,high quality In Ga As/Ga As Sb Type II superlattice for which the optical properties were characterized by photoluminescence at different excitation power and temperature.A blue-shift in luminescence peak energy with excitation power was observed and was described by a non-equilibrium carrier density model.We measured and analyzed the dependences of peak energy and integrated intensity on temperature.Two thermal processes were observed from intensity dependent photoluminescence measurements. In this paper, we report the growth of Ga As Sb and its crystalline property under various Sb2 / As2 flux ratios and growth temperatures. We simulated the incorporation difference between Sb2 and As2 by using a non-equilibrium thermodynamic model. Our study of Ga As Sb growth has successfully yielded, high quality In Ga As / Ga As Sb Type II superlattice for which the optical properties were characterized by photoluminescence at different excitation power and temperature. A blue-shift in luminescence peak energy with excitation power was observed and described by a non-equilibrium carrier density model. We measured and analyzed the dependences of peak energy and integrated intensity on temperature. Two thermal processes were observed from intensity dependent photoluminescence measurements.