Photoluminescence of green InGaN/GaN MQWs grown on pre-wells*

Photoluminescence (PL) characteristics of the structure consisting of green InGaN/GaN multiple quantum wells (MQWs) and low indium content InGaN/GaN pre-wells are investigated. Several PL peaks from pre-wells and green InGaN/GaN MQWs are observed. The peak energy values for both pre-wells and green InGaN/GaN MQWs display an S-shaped variation with temperature. In addition, the differences in the carrier localization effect, defect density, and phonon–exciton interaction between the pre-wells and green InGaN/GaN MQWs, and the internal quantum efficiency of the sample are studied. The obtained results elucidate the mechanism of the luminescence characteristics of the sample and demonstrate the significant stress blocking effect of pre-wells.