In this study, we investigated the effect of well and barrier thicknesses on the optical, structural and electrical properties of multi quantum wells structures and deep-ultraviolet light emitting diodes (DUV-LEDs) through simulation and experiments. DUV-LEDs with different well and barrier thicknesses were simulated to understand the polarization effect and carrier transport characteristics. All the structures were grown on a sapphire substrate using high-temperature metal-organic chemical vapor deposition. The photoluminescence, X-ray diffraction and electroluminescence results showed different optimal well and barrier thicknesses. The photoluminescence and structural properties were superior at well and barrier thickness of 3 nm and 15 nm, respectively, which attributed to the polarization effect, interface and crystal quality. The electroluminescence properties were affected by the carrier transport as well as the crystal quality, showing the highest intensity at well and barrier thickness of 3 nm and 9 nm.