Luminous performance improvement of InGaN/GaN light-emitting diodes by modulating In content in well layers

Abstract

InGaN/GaN triangular shaped multiple quantum wells (MQWs) grown on sapphire substrate were adopted as an active layer of light-emitting diodes (LEDs) by modulating In content in well layers. The temperature dependence of the normalized integrated photoluminescence (PL) intensity showed that the overlap of the electron and hole wave-functions of the LEDs with triangular shaped MQW is much higher than that of the LEDs with conventional rectangular MQW structures, which improves the internal quantum efficiency (IQE) to a certain degree. On the other hand, it was found that the blue shift of the peak energy as a function of injection current is improved for the device with triangular shaped MQW structure from the electroluminescence (EL) spectra of the two series devices. The comparison above indicates that the triangular MQW LEDs are more efficient and more stable.