Investigation of optical and electrical properties of GaN-based blue light-emitting diodes with various quantum well thicknesses

Optical and electrical properties of gallium nitride (GaN)-based blue light-emitting diodes (LEDs) with various indium gallium nitride (InGaN) quantum well (QW) thicknesses were investigated. As the QW thickness was increased, the light output power of GaNbased LEDs also increased. The increase can be attributed to the increase in the carrier radiative recombination rate in the active region. However, the turn-on voltages of these fabricated LEDs are different. This was attributed to the increase in the polarization field with increasing QW thickness. In regard to the hot/cold factor, LEDs with a thicker QWachieved better performance at a low-injection current owing to the lower defect density. The hot/cold factor at a high-injection current would be mainly influenced by the efficiency droop mechanism.