V-pits as Barriers to Diffusion of Carriers in InGaN/GaN Quantum Wells

Abstract

The luminescence characteristics of V-pits in InGaN/GaN quantum wells (QW) correlated directly with the microstructure of the V-pits, as studied by use of transmission electron microscopy with cathodoluminescence. {10-11}-Faceted V-pits, formed in the QW, produce more intense blue-shifted emission than {0001}-plane QW. A dead emission center seems to be present at the corner of the V-pit which connects the R-plane and C-plane QW. High-resolution transmission electron microscopy revealed formation of indium-deficient QW at the corners of the V-pits. High potential barriers occur because of the lack of indium around the hexagonal V-pit; this effectively blocks diffusion of carriers into the threading dislocations known to be non-radiative recombination centers. V-pits thus have promise for improving the internal quantum efficiency of light-emitting diodes.