Effects of lateral overgrowth on residual strain and In incorporation in a-plane InGaN/GaN quantum wells on r-sapphire substrates

We investigated the effects of the patterned lateral over-growth on the residual strain in GaN templates and In incorporation in a-plane InGaN/GaN quantum wells grown on a r-sapphire substrate, by utilizing micro-photoluminescence and Raman scattering spectroscopy. Strong enhancement of emission intensity is observed from the wing area. We report a reduction in the residual strain and different In incorporation in the wing area. The InGaN quantum wells on the merged area have higher In composition with smaller residual strain of the GaN layers underneath.