Light-emitting diodes (LEDs) based on InGaN/GaN multiple quantum wells (MQWs) have attracted considerable attention and entered the market. Blue InGaN/GaN MQWs-based LEDs have an external quantum efficiency (EQE) of 84.3%5. In contrast, InGaN/GaN MQWs-based LEDs which emit light of longer wavelength, usually suffer from a reduction of emission efficiency (that is, the alleged green gap). Therefore, understanding the influence mechanisms of the fluctuating components, or phase separation on the recombination of carriers in the InGaN-related materials is of significant importance towards improving the performance of these optics devices. Relevant research results have been published onScientific Reports,with the article title of “Wave-shaped temperature dependence characteristics of the electroluminescence peak energy in a green inGan-based LeD grown on silicon substrate”. Ph.D. Li Changfu from class 2015 is the first author. Professor Ji Ziwu is the corresponding authors. Shandong University is the completed unit.

In this work,the EL spectra of a green InGaN/GaN MQWs-based LED grown on a Si substrate inwide IC (0.001–350 mA) and temperature (6–350 K) rangeswereinvestigated.It was found that, as the fixed current increasesfrom 0.001 to 350 mA, the dependence of the peak energy on temperature displays a gradual evolution from anapproximately V-shaped temperature dependence to a wave-shaped (three-step blueshift) relationship, until thedependence is changed to an approximately inverted “V shape”. The behavior can be attributed to the presence in the MQW active region of the stronger carrier localization effect. Also, three zones with different degrees of component fluctuation and carrier localization effectsare due to their different average values of In content. The experimental results provide further support for thedevelopment of high-performance LEDs emitting photons at long wavelengths.