Preferential sublimation along threading dislocations in InGaN/GaN single quantum well for improved photoluminescence

InGaN/GaN single quantum wells were grown by molecular beam epitaxy on the silicon substrate onto thin AlN and GaN buffer layers. The InGaN/GaN structure is porosified using a combination of Si_xN_y nanomasking and sublimation and compared with a non-porous reference. The photoluminescence efficiency at room temperature of the porosified sample is improved by a factor reaching 40 compared with the reference sample. Plan-view and cross-sectional transmission electron microscopy images reveal that the remaining material is free of dislocation cores. The regions around dislocations are, thus, preferentially sublimated. This explains the strong photoluminescence improvement of nanoporous InGaN/GaN samples.