Demonstration of 82% relaxed In_0.18G_a0.82N on porous GaN pseudo-substrate by plasma-assisted molecular beam epitaxy

In this study, the impact of InGaN film thickness and different compositionally graded structures on InGaN relaxation grown on tiled GaN-on-porous-GaN pseudo substrates (PSs) were studied. In addition, the impact of the degree of porosification on the In incorporation and relaxation of InGaN were examined. 82% relaxed 1 mu m thick In0.18Ga0.82N, which is equivalent to a fully relaxed In-composition of 15%, on porous GaN PS was obtained. Additionally, multi-quantum wells (MQWs) grown on the MBE InGaN-on-porous GaN base layers by MOCVD showed similar to 85 nm redshift in comparison with MQWs grown on planar GaN. The developed InGaN-on-porous-GaN PSs can provide an alternative route to grow MQW with a high In content which is essential for high-efficiency nitride-based red LEDs.