Fabrication of InGaN/GaN multiple quantum well embedded on nanoporous GaN mirror under different acid electrolytes

Large-size (2 inch) InGaN/GaN multiple quantum wells (MQW) embedded on nanoporous (NP)-GaN distributed Bragg reflectors (DBR) were fabricated by electrochemical (EC) etching at different acid electrolytes (e.g. HF, oxalic, and HNO3 acids). The sample obtained in HNO3 electrolyte presents the highest reflectance and the strongest photoluminescence (PL) intensity, whereas the sample fabricated by the HF etching has uneven surface, leading to very low reflectance. Compared with the as-deposited sample, the HNO3 etching leads to a 5-fold enhancement of PL intensity of etched sample, probably resulting from two factors which reflection of NP-GaN DBR mirror enhanced the light output, and amplify spontaneous emission (ASE) via a resonant cavity increased PL performance.