Three InGaN/GaN quantum wells: S1 (830 ℃), S2 (840 ℃) and S3 (850 ℃) with different barrier temperatures were grown by metal organic chemical vapor deposition (MOCVD). Due to the formation of high-density V-shaped pits, the perfect quantum well structure was destroyed and transformed into InGaN quantum dots (QDs)/quantum well (QW) hybrid structure. Atomic force microscopy (AFM), high-angle annular dark-field imaging (HAADF) and energy dispersive spectrometer (EDS) were employed to analyze the morphology and related causes of the three samples. The changes of quantum confined Stark effect (QCSE), nonradiative recombination center density and carrier localization effect at different barrier temperatures were analyzed by EPDD-PL(excitation power density dependent photoluminescence) and TD-PL(temperature dependent photoluminescence). The results show that QCSE is weaker at lower barrier temperature, because at lower temperature, the V-shaped pits are deeper, inducing more obvious stress release and lower the residual strain. With the increase of barrier growth temperature, the density of nonradiative recombination centers increase gradually. The internal quantum efficiency (IQE) of S1, S2 and S3 samples decrease with the increase of barrier growth temperature. Finally, it is found that the enhancement of QCSE and the higher density of nonradiative recombination centers are the main factors for the decrease of IQE with the increase of barrier growth temperature.