Investigation of strain effect in InGaN/GaN multi-quantum wells

The strain effect of InGaN/GaN multi-quantum wells with different indium contents has been studied in the present paper. The high-resolution X-ray diffraction (HRXRD) curves of the samples have been measured and analyzed by a theoretical model. Based on the model, it is found that sample with higher indium content exhibits a stronger internal strain. To further investigate the calculated results, the injection-current dependent electroluminescence (EL) spectra have been carried out for the samples. An evident blueshift of EL peak energy with increasing current is observed for the sample with higher indium content, implying a stronger quantum-confined-Stark effect and internal strain of it. The inference obtained from the HRXRD line profile analysis is confirmed by the experimental results. The HRXRD can be used as an effective tool to investigate the internal strain of InGaN/GaN MQW heterosystems.