The injection and temperature dependence of the spontaneous emission quantum efficiency of molecular beam epitaxy grown GaAs/AlGaAs heterostructures is determined using excitation dependent photoluminescence (PL) measurements. Two samples are compared; one grown with Sb as a surfactant and one grown without Sb. The PL measurements were performed at temperatures from 80 to 320 K using a HeNe pump laser with powers ranging from 0.6 to 35 mW. The quantum efficiency is inferred from the power law predicted by the rate equations that links pump power and integrated PL signal. The use of Sb as surfactant improved the extrapolated peak spontaneous emission quantum efficiency from 0.970 to 0.977 at 300 K and from 0.996 to 0.998 at 180 K.