Atomic scale characterization of GaInN/GaN multiple quantum wells in V-shaped pits

High-angle annular dark field scanning transmission electron microscopy and atom probe tomography of the V-shaped pits in GaInN/GaN multiple quantum wells have revealed that a quantum well structure exists at the slope region of the V-shaped pits. Their thickness and In concentrations were found to be much lower compared to those of the flat region. This suggests that threading dislocations in the V-shaped pits act as energy barriers for the lateral transport of charge carries and that the pit center may not work properly for vertical transport because of the collapse of well-defined quantum well structures.